Question

[Mbheat77]

Hello, I got a question that I would love to here as many answers to rather your a seasoned vet or new to the hobby. I had a bad algea break about 2 months ago and still battling it. I have somewhat turned the tide to being back to a decent tank, thanks to a couple of cool people I met on this forum. Ok so I am back to doing 5gal water changes every week and am in week 4 of vibrant dosing. I have lost fish and coral due to my tank issues but now that my tank looks better I don't know why this keeps happening. Every water change for the last 3 not including the one just done as of the time of this post. I have lost fish and don't know why. I have a 120gal 6ft long tank and my nitrates and ammonia are good and stable now. I mix my salt at least 24hrs before now thanks to advice but I'm still loosing fish. I lost a clown last week and the 1 that's left is struggling. (This my favorite fish and the longest living) I am almost ready to toss in the towel but I love the hobby. Any suggestions on how I should do the water changes so I don't loose any more fish. The prior changes I did disturb the sand bed alot but this one I just did. I didn't disturb at all. I don't keep a heater in the water while it's mixing because it's in my laundry room where my boiler is and it stays warm in there. That's the only thing I can think of now that I might need to do but water is always around the same temp by feel. Thanks. 

[YHSublime]

Hello @Mbheat77Let me try and summarize here:

• You had a bad algae outbreak 2 months ago.
• You have a 120 gallon 6' tank.
• You do 5 gallon water changes every week.
• You've been dosing vibrant.
• It looks better, but you still have an algae issue. 

Is that all correct? 

• First, how old is your tank? Do you have a photo you can share of your setup? 
• What are you using to test, and what are the numbers? Without this information we're shooting in the dark. 
• What are you using to test salinity? Is it calibrated? 
• What is your water temperature? 
• Do you have an RO/DI? If so, what is your TDS? 
• Tell us a bit more about your setup, is your tank drilled? Do you have a sump? What equipment are you running? What are you using for flow? 
• How many fish do you have, and what/how often do you feed? 

 

Without having any of the above information, I will speculate that 5 gallon water change on a 120 gallon is not a lot, a good rule of thumb is 10% of tanks volume weekly.  

[JMsAquarium]

Phosphates can/may be the cause. Have you tested with a reliable test kit? Phosphates tend to bond to rock and sand bed. If that is your case, the best course of action is to run a GFO media reactor. It will reduce the phosphates levels within a few days. That is providing that all the other levels are within an acceptable range 

[nburg]

I would look more into recent progress with Vibrant - its been shown to be an algicide that can also kill/stress corals, so not exactly reef safe in my book. Everytime you use a bottle of something, it can disturb the balance of a tank, which can then take a while to get back into a health balance, which is when algae can take hold while corals are stunted. 

 

Some times algae is not bad, since they also need the same thing as corals. One approach that I go by is getting things that take care of algae (tangs, crabs, hermits, snails). as the corals grow, they'll out compete the algae. Not always tho - sometime crap in the water can cause algae so a good RO.DI with an up-keep on changing filters can help. 

 

FWIW, I have no algae issues really in my display, but it takes work to keep my inline frag system clean since there i no tang or crabs in there. 

Edited February 21, 2023 by nburg

[Mbheat77]

 Here are some pics of my tank. Had this tank for about 2yrs now. And just recently went bad in like last 3 months. I did have high nitrates at 1 time but now they are fine. I use an ATI test kit, I have a 55gal sump and a older protein skimmer. I have 2 jebao wavemakers and the tank is drilled. My last 3 fish are struggling and might not be here in the morning. I have 2 fire shrimp that are doing well 1 peppermint, about 5 or 6 hermits and 1 emerald left. All my turbo snails are gone by falling off and not being able to turn themselves over. So if I wake up to 3 dead fish I'm starting all over. I snatched them all out and put them in the qt tank but I don't know if that's going be any better. We will see. 

[Origami]

What exactly are your ammonia, nitrite and nitrate levels? What is your salinity? Are you topping off with fresh water? Do you have good surface flow? Are you dosing anything else you've not mentioned? What symptoms/behavior do the fish exhibit when unwell?

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[YHSublime]

8 hours ago, YHSublime said:

 

• What are you using to test, and what are the numbers? Without this information we're shooting in the dark. 
• What are you using to test salinity? Is it calibrated.
• What is your water temperature? 
• Do you have an RO/DI? If so, what is your TDS?  

 

Without having any of the above information, I will speculate that 5 gallon water change on a 120 gallon is not a lot, a good rule of thumb is 10% of tanks volume weekly.  

 

3 hours ago, Mbheat77 said:

 Here are some pics of my tank. Had this tank for about 2yrs now. And just recently went bad in like last 3 months. I did have high nitrates at 1 time but now they are fine. I use an ATI test kit, I have a 55gal sump and an older protein skimmer. I have 2 jebao wavemakers and the tank is drilled. 

 

[Mbheat77]

I have 2 salinity testers. 1 is the one I was given with the tank. I believe it's a tetra and the other 1 I brought is a fluval but I think it's off. I have a rodi filters we're change maybe 8mnths ago. I am new to hobby so don't know what tds means. And water temp is 78

[JMsAquarium]

For salinity, you should use a refractometer

[p3rmafrost]

3 hours ago, Mbheat77 said:

I have 2 salinity testers. 1 is the one I was given with the tank. I believe it's a tetra and the other 1 I brought is a fluval but I think it's off. I have a rodi filters we're change maybe 8mnths ago. I am new to hobby so don't know what tds means. And water temp is 78

TDS = Total Dissolved Solids

Total dissolved solids (TDS) are the amount of organic and inorganic materials, such as metals, minerals, salts, and ions, dissolved in a particular volume of water; TDS are essentially a measure of anything dissolved in water that is not an H2O molecule. This would show you if your RODI filter is leaving something behind that might be impacting your tank.

 

I am by no means an expert, so please take my advice with a grain of salt (pun intended).

 

First - I would strongly suggest going to a local fish store and asking them to test your water. Some of the ones near me do some pretty extensive testing for about $10. Once you have the result post them here so folks can better review your parameters and offer feedback.

 

Second - I would send off for an ICP test. There are several companies who offer them and they're all a little different, but at the end of the day they will tell you exactly what, and how much of it, is in your water. You could have a number of factors that are affecting things that ordinary tests aren't going to show. For example if there is a chunk of metal somewhere it could be breaking down in the saltwater and leeching into your tank.

 

Third - Have you verified all of your equipment is in good working order? Remove it from the tank and inspect everything. I had a pump on a reactor that had a frayed wire that was sending voltage into my tank. That wasn't a good day for many of my inhabitants (or me when I stuck my hand in the sump).

 

Start with the basics and work through it step by step.

 

Hope that helps. I would hate to see someone leave the hobby, especially big ol tank like yours, when this is a problem that can likely be sorted out with some science and patience.

[YHSublime]

3 hours ago, Mbheat77 said:

I have 2 salinity testers. 1 is the one I was given with the tank. I believe it's a tetra and the other 1 I brought is a fluval but I think it's off. I have a rodi filters we're change maybe 8mnths ago. I am new to hobby so don't know what tds means. And water temp is 78

 

While a hydrometer is fine for testing, they do become off over time, and can't be calibrated. A refractometer is best, and relatively cheap. So your salinity might be off, and the water your making might be part of the culprit, especially if you don't know if your RO/DI is doing the job it's supposed to do. 

 

We can speculate left and right, but still looking for numbers:

18 hours ago, YHSublime said:

What are you using to test, and what are the numbers? Without this information we're shooting in the dark. 

 

10 hours ago, Origami said:

What exactly are your ammonia, nitrite and nitrate levels? What is your salinity? Are you topping off with fresh water? Do you have good surface flow? Are you dosing anything else you've not mentioned? What symptoms/behavior do the fish exhibit when unwell?

 

 

 

[Mbheat77]

So my last and first clown I bought died. So I'm down to a single cardinal. 😩 but here are some numbers from a test a friend let me use. Hope this will get me closer. I also have another question since my fish are all dead and I think the sand could be the culprit can I just take the sand out and put new sand in the tank or can I just disturb it real good and clean it with water changes. 

[lynn.reef.nerd]

What is your salinity. I don't think you have answered that yet. 

 

How do you mix your salt? do you just add a certain amount of salt to water and not check salinity? 

Do you check the salinity after you mix the salt? 

[Origami]

Nitrates and phosphates aren't high enough to be a problem for fish.

How long before a fish starts exhibiting symptoms (from the time you put it in the tank)? What are the symptoms (e.g., fast breathing, uncoordinated swimming, lethargy)? Any signs of discoloration on their bodies or gills? Some discoloration might look like bruising, or flecks of salt, or even like a coating of powdered sugar for example. Marine velvet, for example, can obliterate a tankful of fish in a matter of days.

How often do you feed? Is it all consumed, or does waste settle onto the sand and in the corners? You have a lot of algae growth in some pics.

Do you have any inverts living/thriving in the system (snails, crabs, etc.)?

If the fish start exhibiting problems fairly quickly after being put in the tank, please test for ammonia and nitrite.

I think somebody suggested you take a sample of your water to an LFS for testing. I'd do that soon.

See the other unanswered questions in previous post and respond as quickly and as accurately as you can. Some key questions whose answers should be easy remain unanswered.

Sent from my Note 10+5g using Tapatalk

[nburg]

How have your fish been acting before they die? strong breathing, while spots? funny swimming, red sores? anything out of the ordinary?

 

Could be some sort of disease and water changes stress them or could be coincidence. 

 

If fish are dying but not shrimp, I am wonder if there is a fish pest. Or I have heard of unmixed salt crystals affecting fish. 

[Newfishgirl]

I didn’t see the answer anywhere but what/where are you getting the water you are mixing your new water from? I had an issue in the past, have some now cause haven’t had a chance to replace the filter in my RO/DI chamber. It throws it off just enough to wreak havoc with algae growth. It’s just a thought. Also, maybe you don’t have enough bacteria in your tank with all the water changes and Vibrant use. Don’t give up hope on your tank. We all go through this at some point. It’s frustrating for sure but hang in there.


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[Mbheat77]

Ok thanks to all. I'll try and answer what I can. 1st I did get an ATI test kit to send my water off and I am sending that off today. Now I do have a rodi system and my filters were change maybe 6 to 8mnths ago. White filter in the 1st chamber is still Fairley white. 2nd I mix my water in a 30gal hyper tough plastic trash can I bought from Walmart. I mix my salt for at least 2days lately. I keep the powerhead circulating the water the whole time. I don't use a heater cause the room stays warm cause it's my laundry room and I have oil heating so boiler keeps it nice in there. My salinity is good but a little lower than I would want it but still inside the range. I don't know the numbers off hand but I use the plastic one u fill up and the arm floats where it tells u the number. It's inside of the range just towards the bottom. Now as for my fish when I change the water they seem to get low in the water and start breathing heavy. It's sometimes as I'm filling the water back in or sometimes a little later. In my last I would say 5 water changes I have lost a fish each time. So frustrating cause I get attached to them and it's hard to keep getting them only for them to die. So a friend had told me to disturb the sand little by little each change because I wasn't cleaning it right for the 2 yes I had the tank. I was only just grazing the top of the sand. So now I have been trying to clean it each water change. But this last time I didn't disturb it to much. So I'm lost to what  is causing this. The weird part is once everything settles a day or 2 after the change everything is doing good fish are swimming around normally. It's just that rough time when I add the water. I was feeding to much which led to the algae about a month ago. But I had 11 fish and the food was being eaten up pretty much in a couple of min. So that's when my lfs owner tested and said I was feeding to much and feed less. So I did that and was only feeding half a cube every day. Now that I only had a couple fish I only was feeding a piece of the block. I am only feeding frozen, and switch the kind up each time but that is it. When I had all the fish I would drop a couple pellets done for the shrimp but it was only like 3 small pellets and half the time the clowns would eat them. So I really am trying to get this tank back right I miss my fish. It's my relaxing time when I just sit and watch them. Now I'm suffering 😪 but I am not going give up just want to get it right and find out what's going on. Hope I answered all the questions. Thanks again. 

[Mbheat77]

3 hours ago, Newfishgirl said:

I didn’t see the answer anywhere but what/where are you getting the water you are mixing your new water from? I had an issue in the past, have some now cause haven’t had a chance to replace the filter in my RO/DI chamber. It throws it off just enough to wreak havoc with algae growth. It’s just a thought. Also, maybe you don’t have enough bacteria in your tank with all the water changes and Vibrant use. Don’t give up hope on your tank. We all go through this at some point. It’s frustrating for sure but hang in there.


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3 hours ago, nburg said:

How have your fish been acting before they die? strong breathing, while spots? funny swimming, red sores? anything out of the ordinary?

 

Could be some sort of disease and water changes stress them or could be coincidence. 

 

If fish are dying but not shrimp, I am wonder if there is a fish pest. Or I have heard of unmixed salt crystals affecting fish. 

 

11 hours ago, Origami said:

Nitrates and phosphates aren't high enough to be a problem for fish.

How long before a fish starts exhibiting symptoms (from the time you put it in the tank)? What are the symptoms (e.g., fast breathing, uncoordinated swimming, lethargy)? Any signs of discoloration on their bodies or gills? Some discoloration might look like bruising, or flecks of salt, or even like a coating of powdered sugar for example. Marine velvet, for example, can obliterate a tankful of fish in a matter of days.

How often do you feed? Is it all consumed, or does waste settle onto the sand and in the corners? You have a lot of algae growth in some pics.

Do you have any inverts living/thriving in the system (snails, crabs, etc.)?

If the fish start exhibiting problems fairly quickly after being put in the tank, please test for ammonia and nitrite.

I think somebody suggested you take a sample of your water to an LFS for testing. I'd do that soon.

See the other unanswered questions in previous post and respond as quickly and as accurately as you can. Some key questions whose answers should be easy remain unanswered.

Sent from my Note 10+5g using Tapatalk
 

 

13 hours ago, lynn.reef.nerd said:

What is your salinity. I don't think you have answered that yet. 

 

How do you mix your salt? do you just add a certain amount of salt to water and not check salinity? 

Do you check the salinity after you mix the salt? 

Ok thanks to all. I'll try and answer what I can. 1st I did get an ATI test kit to send my water off and I am sending that off today. Now I do have a rodi system and my filters were change maybe 6 to 8mnths ago. White filter in the 1st chamber is still Fairley white. 2nd I mix my water in a 30gal hyper tough plastic trash can I bought from Walmart. I mix my salt for at least 2days lately. I keep the powerhead circulating the water the whole time. I don't use a heater cause the room stays warm cause it's my laundry room and I have oil heating so boiler keeps it nice in there. My salinity is good but a little lower than I would want it but still inside the range. I don't know the numbers off hand but I use the plastic one u fill up and the arm floats where it tells u the number. It's inside of the range just towards the bottom. Now as for my fish when I change the water they seem to get low in the water and start breathing heavy. It's sometimes as I'm filling the water back in or sometimes a little later. In my last I would say 5 water changes I have lost a fish each time. So frustrating cause I get attached to them and it's hard to keep getting them only for them to die. So a friend had told me to disturb the sand little by little each change because I wasn't cleaning it right for the 2 yes I had the tank. I was only just grazing the top of the sand. So now I have been trying to clean it each water change. But this last time I didn't disturb it to much. So I'm lost to what  is causing this. The weird part is once everything settles a day or 2 after the change everything is doing good fish are swimming around normally. It's just that rough time when I add the water. I was feeding to much which led to the algae about a month ago. But I had 11 fish and the food was being eaten up pretty much in a couple of min. So that's when my lfs owner tested and said I was feeding to much and feed less. So I did that and was only feeding half a cube every day. Now that I only had a couple fish I only was feeding a piece of the block. I am only feeding frozen, and switch the kind up each time but that is it. When I had all the fish I would drop a couple pellets done for the shrimp but it was only like 3 small pellets and half the time the clowns would eat them. So I really am trying to get this tank back right I miss my fish. It's my relaxing time when I just sit and watch them. Now I'm suffering 😪 but I am not going give up just want to get it right and find out what's going on. Hope I answered all the questions. Thanks again. 

[p3rmafrost]

Couple of things to add -

The thing with the floaty arm to check salinity is a hydrometer. My understanding (someone please correct me if I'm incorrect) is that there are many factors that can cause false readings with them. For example, bubbles on the indicator or salt binding the pivot point. I strongly suggest picking up a refractometer, calibrate it, and check your salinity again. You can get a refractometer at your LFS, Petco, or Petsmart. They generally run about 30 bucks, it isn't a costly investment to rule out salinity as a cause of your issues.

 

https://www.petco.com/shop/en/petcostore/product/imagitarium-aquatic-refractometer-2703720?cm_mmc=PSH|GGL|CAL|SBU05|0|OB-Imagitarium|ncG8e7Xkwp8mA74QnAc53b|||0|0|||18278802365&gclid=CjwKCAiAl9efBhAkEiwA4TorinTxvs23eGJp4IwyYTM55JR_Q-8aR9IOeEnYFb3rNqncskxrY3MZkhoCWX8QAvD_BwE&gclsrc=aw.ds

 

Another thing on salinity: My salt specifically tells you to measure salinity at a certain temperature when you mix it. You mentioned you're not using a heater, but have you ever measured the temperature of the water? If it is warmer or cooler than your tank it might have an impact. Are you measuring the salinity before you add it to the tank, then measuring the display tank salinity when you're done? You want to make sure you're not having big swings. I recently went through this because of a gummed up nozzle on my ATO, my salinity rose 1.030, I dropped it with a water change much faster than I should have and the corals were not happy.

 

The ATI ICP test was a good move. It'll take a while to get results back. I think they get shipped to California then forwarded to the lab in Germany (unless you paid for your own label and sent it directly to Germany). In the meantime I still suggest having the LFS run a full test on the tank.

 

Did you check your equipment for damage? Do you have a voltmeter? If so, ground the black probe and stick the red one in the water and see if you have voltage in your tank.

 

Stirring up the sand bed can release built up gasses, but I believe you really need a sand bed that is 3 inches or more for anaerobic gasses to build up. I've seen a lot of threads discussing whether or not that's a myth. Some folks say gas bubbles build up and when released convert nitrates to nitrogen but can also create sulfide. Other folks disagree and say that isn't accurate. When I change my water (every Sunday) I vacuum the sand bed and it ends up getting quite agitated. I have never had any issues with anything being released that impacted the fish or the corals, except for phosphates. Stirring up the detritus and bits of uneaten food does cause a phosphate spike for a short period. That shouldn't have a significant impact on your fish though.

 

This is kind of a side note, and likely unrelated to any of your issues, but if you had 11 fish and were feeding a half cube a day, that sounds really low to me. My fish (I have 7) eat 2 cubes in the morning and 2 cubes at night. They're getting significantly more food than yours and I am not experiencing the same problems you're having. Do your fish look skinny? Is there a possibility they're starving? Someone who is more experienced might have more to add on this.

[howaboutme]

I suggest you get a refractometer as the very first step. Rule out salinity. Then we can figure out next steps. Even if you start over, you should use a refractometer moving forward.

[p3rmafrost]

35 minutes ago, howaboutme said:

I suggest you get a refractometer as the very first step. Rule out salinity. Then we can figure out next steps. Even if you start over, you should use a refractometer moving forward.

[Mbheat77]

2 hours ago, p3rmafrost said:

Couple of things to add -

The thing with the floaty arm to check salinity is a hydrometer. My understanding (someone please correct me if I'm incorrect) is that there are many factors that can cause false readings with them. For example, bubbles on the indicator or salt binding the pivot point. I strongly suggest picking up a refractometer, calibrate it, and check your salinity again. You can get a refractometer at your LFS, Petco, or Petsmart. They generally run about 30 bucks, it isn't a costly investment to rule out salinity as a cause of your issues.

 

https://www.petco.com/shop/en/petcostore/product/imagitarium-aquatic-refractometer-2703720?cm_mmc=PSH|GGL|CAL|SBU05|0|OB-Imagitarium|ncG8e7Xkwp8mA74QnAc53b|||0|0|||18278802365&gclid=CjwKCAiAl9efBhAkEiwA4TorinTxvs23eGJp4IwyYTM55JR_Q-8aR9IOeEnYFb3rNqncskxrY3MZkhoCWX8QAvD_BwE&gclsrc=aw.ds

 

Another thing on salinity: My salt specifically tells you to measure salinity at a certain temperature when you mix it. You mentioned you're not using a heater, but have you ever measured the temperature of the water? If it is warmer or cooler than your tank it might have an impact. Are you measuring the salinity before you add it to the tank, then measuring the display tank salinity when you're done? You want to make sure you're not having big swings. I recently went through this because of a gummed up nozzle on my ATO, my salinity rose 1.030, I dropped it with a water change much faster than I should have and the corals were not happy.

 

The ATI ICP test was a good move. It'll take a while to get results back. I think they get shipped to California then forwarded to the lab in Germany (unless you paid for your own label and sent it directly to Germany). In the meantime I still suggest having the LFS run a full test on the tank.

 

Did you check your equipment for damage? Do you have a voltmeter? If so, ground the black probe and stick the red one in the water and see if you have voltage in your tank.

 

Stirring up the sand bed can release built up gasses, but I believe you really need a sand bed that is 3 inches or more for anaerobic gasses to build up. I've seen a lot of threads discussing whether or not that's a myth. Some folks say gas bubbles build up and when released convert nitrates to nitrogen but can also create sulfide. Other folks disagree and say that isn't accurate. When I change my water (every Sunday) I vacuum the sand bed and it ends up getting quite agitated. I have never had any issues with anything being released that impacted the fish or the corals, except for phosphates. Stirring up the detritus and bits of uneaten food does cause a phosphate spike for a short period. That shouldn't have a significant impact on your fish though.

 

This is kind of a side note, and likely unrelated to any of your issues, but if you had 11 fish and were feeding a half cube a day, that sounds really low to me. My fish (I have 7) eat 2 cubes in the morning and 2 cubes at night. They're getting significantly more food than yours and I am not experiencing the same problems you're having. Do your fish look skinny? Is there a possibility they're starving? Someone who is more experienced might have more to add on this.

Thanks I am going to get a new tester for my salinity. And I am going to start keeping water the same temp also with heaters. When I had 11 fish I was doing a whole cube. Only dropped as I lost fish. Lfs tested my water and told me to lighten up on feeding. My nitrates were high. I have nitrates and ammonia at the right level. Sand bed is a whole nother issue. For 2 yes I didn't move Sand would only skim top. Now it's is packed and stiffer that before. U mentioned u change yours every Sunday. That's what I wasn't doing. I'm going to try and mix it up real good and do a 75% water change after I get my results back to rule out anything else. I'm getting a salinity checker so from this point on I will make sure they are identical numbers. Thanks again

[Mbheat77]

1 hour ago, howaboutme said:

I suggest you get a refractometer as the very first step. Rule out salinity. Then we can figure out next steps. Even if you start over, you should use a refractometer moving forward.

Thanks I am getting 1

[p3rmafrost]

24 minutes ago, Mbheat77 said:

Thanks I am getting 1

Make sure you calibrate it. It might be different with each model but you generally put either calibration fluid or RODI water into the refractometer then use a screwdriver that will come in the kit to adjust it to the proper reading. Check over the instructions and set it up properly. You'll want to double check it once a month or so to make sure it's still calibrated. Let us know what you find out!

[JMsAquarium]

34 minutes ago, Mbheat77 said:

Thanks I am getting 1

And also get a bottle of calibration liquid. It's only a few $$. I calibrate mine once a month and miner adjustments are almost always needed. A refractometer and calibration fluid is one of the cheapest and safest investments that you will ever make in this hobby. Always test your tank water AND your new saltwater mix to ensure that they are at the same salinity levels before you do a water change.

 

This is the refractometer that I have

 https://www.amazon.com/Refractometer-Fishkeeping-Automatic-Temperature-Compensation/dp/B018LRO1SU/ref=sr_1_1_sspa?crid=1ZE3OQY9D4QJ5&keywords=refractometer+for+saltwater+aquarium&qid=1677093486&sprefix=refractometer+for+saltwater+aquarium%2Caps%2C502&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyVDdMMEhUQTZLU05UJmVuY3J5cHRlZElkPUEwMzcyMjg4MlQ1NVVROFdTV0VaSCZlbmNyeXB0ZWRBZElkPUEwMjc3NzY3QjY5TkMzREJQRFFIJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==#:~:text=Submit-,Salinity Refractometer for Seawater and Marine Fishkeeping Aquarium 0-100 PPT with Automatic Temperature Compensation,-Visit the Agriculture

 

And the calibration fluid 

https://www.amazon.com/AccuBrate-Refractometer-Salinity-Calibration-Fluid/dp/B07HQSY9QG/ref=sr_1_5?crid=1ZE3OQY9D4QJ5&keywords=refractometer+for+saltwater+aquarium&qid=1677093617&sprefix=refractometer+for+saltwater+aquarium%2Caps%2C502&sr=8-5#:~:text=VIDEO-,AccuBrate Refractometer Salinity Calibration Fluid – 60 ml Solution to Accurately Calibrate Refractometer for Testing Natural Saltwater or Synthetic Sea Water - Made in the USA (60 ml),-Visit the Aquatic