Reef Chemistry

[AndrewRyan]

I’ll try to keep this concise, but as it’s a complicated problem it may be not be easy.

 

I have a system that is now a little over two months old. I realize it’s very much establishing itself and I also intended going in to use water changes for the first few months to replenish alkalinity and calcium. That said, I did purchase a DOS to go along with my Apex and Trident mowing that at some point dosing would need to take place.

 

My first batch of Fritz RPM salt was measuring lower in alkalinity than I had hoped for whatever reason (around 7ppm). I decided to raise the alkalinity by initially dosing part 1 of ESV B-Ionic to raise Alk. It worked a treat, brought my Alk to ~8.5 and all seemed good. But then I noticed that not only am but calcium was beginning to drop. Not wanting to be unbalanced I started dosing part 2 as well as part 1 (roughly 50% of dose for part 2 compared to part 1 or 10ml/5ml to start).

 

However, I have noticed recently that it’s dropping a little more each day and I have adjusted dosing to support this continued drop. I got concerned when I reached twenty ml per day of each wondering if this was normal or if the increased dosing would ever stop.

 

I have many indicators that point to precipitation being a problem (CO2 scrubber pinning PH from 8.2-8.3, 79-80 degree water temp, etc) and I do see some “build up” along the floor of my sump. However this is generally spread throughout the sump, not just where the dosing lines come in, and I do have a Wrasse which kicks up my fairly fine sand pretty frequently.

 

I stopped all dosing for a couple days on Wednesday to see what the tank would do and it dropped into the 6s at a pretty steady rate. Calcium dropped to 385 from the 415-435 range I generally wanted to aim for as well.

 

I guess what confuses me is that I wouldn’t think that I wouldn’t need to dose 20 ml per day of each part in my 2 month old 55 gallon system. I also don’t want to maintain alkalinity less than 7 in my system which apparently requires dosing. I lost roughly .7 dKH per day when I ceased dosing with a corresponding decline in CA.

 

Its probably helpful to also note that I have been religious with a 10% water change each Sunday so I’m not just relying on dosing. Also helpful to know I have a good deal of LPS coral that has been added to the system, but no SPS. I also don’t see any coralline algae at this point which I know can increase demand.

 

Grateful for any thoughts.

 

 

Sent from my iPhone using Tapatalk

[WheresTheReef]

At what salinity are you mixing your salt to? Looks like at 35ppt the alk should be 8-9dkh. At a lower salinity the alk level would also be lower. A newer tank like yours will consume alk due to an incomplete nitrogen cycle. It takes much longer for the anaerobic bacteria to establish, and it is this final step that returns the consumed alk back into your system. It took my tank a year to complete the cycle.

 

What is your tank’s Mg level? If it’s too low it could be one reason why the Ca was dropping as you dosed just alk due to precipitation.
 

Make sure and space alk and Ca dosing far enough apart (e.g. 0.5-1hr apart) to reduce precipitation. It also helps to put a powerhead in the sump chamber you’re dosing into so the solution mixes well with the tank water.

[howaboutme]

Are you double checking the Trident's reading with another test kit? Just want to rule that out too.

[AndrewRyan]

24 minutes ago, howaboutme said:

Are you double checking the Trident's reading with another test kit? Just want to rule that out too.

I did double check more frequently at first with the trident, but now I’m comfortable using it as trend analysis.  I’m not too uncomfortable if it’s off a bit from the Hanna (which it hasn’t yet been), just looking for it to stay stable.

[AndrewRyan]

13 hours ago, WheresTheReef said:

At what salinity are you mixing your salt to? Looks like at 35ppt the alk should be 8-9dkh. At a lower salinity the alk level would also be lower. A newer tank like yours will consume alk due to an incomplete nitrogen cycle. It takes much longer for the anaerobic bacteria to establish, and it is this final step that returns the consumed alk back into your system. It took my tank a year to complete the cycle.

 

What is your tank’s Mg level? If it’s too low it could be one reason why the Ca was dropping as you dosed just alk due to precipitation.
 

Make sure and space alk and Ca dosing far enough apart (e.g. 0.5-1hr apart) to reduce precipitation. It also helps to put a powerhead in the sump chamber you’re dosing into so the solution mixes well with the tank water.

I have my salinity pegged at 1.026 or 35 ppt and that’s what I mix the salt at.  Magnesium actually started to drop a bit at one point as well (not much) but I dosed it back to ~1350 which is where I have been keeping it plus or minus 20-30 or so.  I have actually heard that all magnesium tests have a +/- of 150 so I just try to keep it reading roughly the same.

 

The 2 parts are set up to dose at least 5 minutes apart and these are really small micro doses throughout the day with the DOS. I don’t have a power head in the sump but both lines are run into the baffle between skimmer chamber and return so there’s adequate flow there.

[WheresTheReef]

Is what you’re seeing precipitation for sure or detritus? If it’s precipitation then you need to address that. That Mg level seems ok. Are you seeing precipitation on the sump walls, heaters and/or pump? If it’s precipitation then consider spacing your dosing more than 5 mins apart, maybe at least 30 mins. At your dosage it’s overkill to have such small dosing and it’s better to space them apart. I’m also not sure how accurate the DOS is at such small dosages.

 

It’s perfectly normal for you to be dosing more Alk than Ca due to an incomplete nitrogen cycle. Can you provide a picture of your tank? With a fully cycled tank, I would expect a tank mostly stocked with LPS to be able to replenish consumption of elements through water changes. Once the anaerobic bacteria establishes then you will see Alk consumption stabilize and maybe reduce. 
 

Do you have any clams? They can consume lots of trace elements when it’s happy and growing.

[zygote2k]

As mentioned previously, how long did you let the tank cycle? 
IME, tanks that are cycled correctly allow for more stable water chemistry.

A proper cycle takes 60-120 days, but most aquarists don’t have the patience for this and end up with issues.

Pick a good salt mix and stick with it.

Instant Ocean is great.

Use high quality test kits like Salifert or LaMotte and keep a detailed log.

Dose your Alk, Ca, Mg at 8 hour spaces to prevent precipitation.