How to LOWER Alk in freshly mixed water

[BowieReefer84]

Question:

 

How do I lower the Alk in freshly mixed saltwater.  Right now I have 3gal of freshly mixed instant oceans (1.026) and the Alk is at 11.2.  I want to lower it to a range around 9.0.

 

What do I add and how much.  I searched online a bit, but figured I would get others input on here as well.  I am going to test it in the mixing water, and not directly in the tank.  So, this is practice more than anything.

 

The end goal is to keep my tank Alk at 9.0 when the salinity is 1.026, and not have any swings in that because of a water change with different parameter water.  

 

Thanks

 

Edit - This (http://www.advancedaquarist.com/2002/2/chemistry) is the article I read, but it is over my head in terms of chem.

Edited October 19, 2013 by BowieReefer84

[Cliff Puckstable]

I've read that muriatic acid will lower the alk but it will also lower the ph. Most people I've talked to don't compensate for the difference for their wc's and just go for it.

[zygote2k]

test it (fresh saltwater) after 24 hours and see if the ALK drops.

[lnevo]

If it's reef crystals thats what it mixes at I believe. Try instant ocean regular which has lower cal and alk. Your other option is ESV salt which lets you mix to exactly the parameters you want. I'm not sure how available that is in your area, I know it's a Long Island based company but it's very popular up here.

 

Finally, i would just find a salt that matches the parameters your after. That would be the easiest.

[Cliff Puckstable]

Regular IO mixes at 11dkH, Ca- 370.

 

http://wamas.org/forums/topic/60341-io-salt-mix/

[lnevo]

I read 10.2 in that thread...anyway how much water change are you doing? It should skewed that much..

 

Look into ESV though...lot of people round here are extremely happy with it and you can mix it to your exact Cal and Alk parameters.

 

And the price is high but it makes 200 gallon at 1.025 whereas IO is measured at 1.021 so you do get some offset there.

[BowieReefer84]

test it (fresh saltwater) after 24 hours and see if the ALK drops.

I will do that, and report back tomorrow evening.

 

If it's reef crystals thats what it mixes at I believe. Try instant ocean regular which has lower cal and alk. Your other option is ESV salt which lets you mix to exactly the parameters you want. I'm not sure how available that is in your area, I know it's a Long Island based company but it's very popular up here.

 

Finally, i would just find a salt that matches the parameters your after. That would be the easiest.

It is Instant Ocean mixing at 11.2 (according to my eye on the salifert test kit)

 

ESV isn't something I have looked into, but that's a nice option.  I thought Instant Ocean would mix lower towards my goal parameters.  Was surprised the amount of Alk in 1.026 water.

 

Regular IO mixes at 11dkH, Ca- 370.

 

http://wamas.org/forums/topic/60341-io-salt-mix/

Yup, that's what I got.

 

I read 10.2 in that thread...anyway how much water change are you doing? It should skewed that much..

 

Look into ESV though...lot of people round here are extremely happy with it and you can mix it to your exact Cal and Alk parameters.

 

And the price is high but it makes 200 gallon at 1.025 whereas IO is measured at 1.021 so you do get some offset there.

I am changing 15%-20%.  My tank only has 20gal of water with the sump, so the price difference going to ESV would not be a big deal really.  I like the fact Instant Ocean is so widely used in successful tanks.

 

 

SOOOO, the question remains.  How can I lower the Alk if I stick with Instant Ocean?

[Origami]

First, I would let the mix stabilize for 24 hours with an airstone running in it first before trying this. But, IO does mix up to about 11 dKH these days.

 

Looking at your question, it seems like it's a titration problem:

 

You have 3 gallons (11.26 liters) at 11.2 dKH. You'd like to bring that down to 9 dKH - a drop of 2.2 dKH. Since 2.8 dKH = 1 meq/liter, that's a drop of 0.8 meq/liter. Given that you have 11.26 liters of solution there, your goal is to neutralize 9.1 milliequivalent of alkalinity.

 

The muriatic acid that you can get at Lowe's is very strong. Its 20 Baume (31.45% HCl) is so strong, it's fuming. Look up 20 Baume HCl and you find it's 10.17 molar, or 10.17 moles of HCl in every liter of solution. (This is like the stuff that your high school chemistry teacher kept in the locked cabinets away from the students.) For HCl, 1 milliequivalent = 1 millimole, thus the HCl from Lowes is 10,170 meq/liter. or 10.17 meq/ml. Thus, to neutralize 9.1 meq of alk, you will need 0.89 milliliters of fuming hydrochloric (aka muriatic) acid.

 

Now, I suspect that the acid from Lowe's probably varies in concentration - I don't know for sure. But, if you dilute it by pouring 1 part acid into 9 parts water (ALWAYS acid into water, not water into acid), you can use 8.9 ml of the diluted solution. Using a diluted solution is going to be more forgiving for volume errors.

 

Aerate the water afterwards to blow off the CO2 that's created in the process.

[BowieReefer84]

Tom, thank you!  I followed that pretty good after reading the article I linked.

 

The pump I use to mix the water has an airline attachment that I use (similiar to a skimmer venturi), so I DO use that.  I will measure again tomorrow afternoon once it has been 24 hours to see where I am at.

 

Would it be more feasible to add vinegar to drop the PH rather than the diluted MA?  I have never used MA, and honestly feel more comfortable with vinegar.  However, I know the MA is cheap.  I could mix it 1 part to 9 parts water in a jug and have enough to last a LONG time.

 

Again, thank you.

[BowieReefer84]

PS - Stop editing when I can't see it's been edited... haha

 

Edit- I have syringes with 1ml-5ml readings so I can get a good accurate dose.

Edited October 20, 2013 by BowieReefer84

[Origami]

 

Would it be more feasible to add vinegar to drop the PH rather than the diluted MA?  I have never used MA, and honestly feel more comfortable with vinegar.  However, I know the MA is cheap.  I could mix it 1 part to 9 parts water in a jug and have enough to last a LONG time.

Yes, but vinegar is even less controlled and I'm not sure just how much you would use to be honest, because it's such a weak acid (low dissociation constant) and may continue to dissociate as it chewed up alkalinity. It would be trial and error probably to get it right.

 

I always have a few gallons of muriatic acid around because it's got so many uses (cleaning masonry, chimney caps, and aquarium equipment). It's extremely potent and dangerous if handled incorrectly or not securely stored. Thus, I completely understand (and respect) people's caution when considering its use. If you do choose to use it, be aware that it is fuming HCl. Thus, you want to be in a well ventilated area when pouring it out. Wear safety glasses and gloves.

 

PS - Stop editing when I can't see it's been edited... haha

 

Edit- I have syringes with 1ml-5ml readings so I can get a good accurate dose.

LOL. I found a couple of typos I wanted to correct and clarifications / additions that I felt were good to make.  Again, keep in mind that the HCl from Lowes is not lab-grade stuff. While it's supposed to be 10.17 molar, it might be a little more or a little less.

 

This was a math exercise for me. Hopefully it's accurate. Give it a try, but don't be surprised if you need a little more or less (in which case you can toss in some baking soda to bring alk back up).

[BowieReefer84]

Yea, maybe I will get some MA mix it out at 9 parts water to 1 part acid and discard the rest.  I don't have kids or pets so it's not a big concern, just that it's not something I have handled before.

 

I don't need it exact, but it would be nice to be between 8,5 - 9.5 Alk with the new water instead of 11.

 

Can I pour the diluted mixture inside? 

 

Edit - Can I keep the diluted mixture in a plastic container?

Edited October 20, 2013 by BowieReefer84

[Origami]

Can I pour the diluted mixture inside?

Yes. This shouldn't be a problem.

 

Edit - Can I keep the diluted mixture in a plastic container?

Also yes.

[Origami]

Lowe's has a gallon of the stuff for about $7 or so if I recall correctly. It's got a blue label around the jug and it's made by Crown. You'll find it in the paint department.

Here it is. Good stuff, but very strong.

 

They've got another that I've not used. It's "safer" - meaning it's diluted. In this case, it's concentration is cut. Because the Baume scale is not linear, you can't simply take this 10 Baume stuff and double the amount used as compared to the other stuff.

[zygote2k]

here's another question-

what happens when you put the high alk water into the tank? does it spike the alk as I would think, but then settles back to the norm?

If so, it's not something that I would worry about as it will keep the ALK stable. This way you don't have to dose ALK to bring it up.

Have you been recording your test results weekly and then see what happens to ALK after w/c?

If it's too high, then your test results would show a gradual rise in ALK if not being consumed, but if ALK demand is moderate or high, then your results might show a flatline of ALK.

 

I would do this before dosing acid to lower the pH and ALK.

[Jason Rhoads]

here's another question-

what happens when you put the high alk water into the tank? does it spike the alk as I would think, but then settles back to the norm?

If so, it's not something that I would worry about as it will keep the ALK stable. This way you don't have to dose ALK to bring it up.

Have you been recording your test results weekly and then see what happens to ALK after w/c?

If it's too high, then your test results would show a gradual rise in ALK if not being consumed, but if ALK demand is moderate or high, then your results might show a flatline of ALK.

 

I would do this before dosing acid to lower the pH and ALK.

 

 

+1 I totally agree here. 

[lnevo]

+2

 

I would also add that its much easier to maintain the alk at the params your salt will provide then trying to get your fresh saltwater to match an arbitrary value. If you want to match your water and are dosing, slowly bring your tank to 10-11 and then you'll match your water

[OldReefer]

The high Alk levels are what caused me to switch salts.

 

I went to D-D H2O because it mixes up exactly to the same parameters I run my tank at. I used to have my Alk and Ca bounce all over the place every time I did a water change. Now they stay rock steady. SPS really seem to like that. It is a nice salt mix, but stupid expensive.

[BowieReefer84]

here's another question-

what happens when you put the high alk water into the tank? does it spike the alk as I would think, but then settles back to the norm?

If so, it's not something that I would worry about as it will keep the ALK stable. This way you don't have to dose ALK to bring it up.

Have you been recording your test results weekly and then see what happens to ALK after w/c?

If it's too high, then your test results would show a gradual rise in ALK if not being consumed, but if ALK demand is moderate or high, then your results might show a flatline of ALK.

 

I would do this before dosing acid to lower the pH and ALK.

 

Currently the tank is low at 7.6.  I started dosing two part to bring it up.  My tank has a few sps frags that must be using it up right now.  I think it's droping like .3 per day if my calc are correct so far, and will only drop more once I add more frags.

 

The goal is to keep it rock solid at 8.4-8.6ish range I hear is a good number.  I want to pick a number and shoot for stability around that number.

 

The problem is I didn't expect the Instant Ocean to mix so high.  I thought it would be mixing around what I wanted to keep the tank at.  I guess I could look in the DD H20 salt or the ESV salt, and start using those for waterchanges.

 

Thank goodness it's such a small tank, and any salt I chose will last a long time for me compared to those of you with 120's and 180's.  

[BowieReefer84]

+2

 

I would also add that its much easier to maintain the alk at the params your salt will provide then trying to get your fresh saltwater to match an arbitrary value. If you want to match your water and are dosing, slowly bring your tank to 10-11 and then you'll match your water

 

I had good success in the past keeping it at 8.4-8.6, and would rather continue to maintain that level than match such a high level.  

[BowieReefer84]

The high Alk levels are what caused me to switch salts.

 

I went to D-D H2O because it mixes up exactly to the same parameters I run my tank at. I used to have my Alk and Ca bounce all over the place every time I did a water change. Now they stay rock steady. SPS really seem to like that. It is a nice salt mix, but stupid expensive.

So exactly what is your Calc, Alk, Mag with the DD H20?

[lnevo]

According to their docs its still in the 10-11 range but thats mixed at 35.5

 

http://www.theaquariumsolution.com/h2ocean-natural-reef-salt-23kg-bucket

[BowieReefer84]

Tested again and Alk is stable at 11 and Calc is 380.

[ridetheducati]

Tested again and Alk is stable at 11 and Calc is 380.

 

How much HCL did you use?

[BowieReefer84]

How much HCL did you use?

None yet.  I let the water mix for 24 hours, and those are the numbers I have gotten.  I picked up some of the Muriatic Acid earlier today.  Going to add 100ml MA to 900ml of water and then add 6ml of that mixture (Tom recommended 9ml).  I figure I can always add more, and I will do a few tests tomorrow and report back.

 

I will re-test both Calc and Alk tomorow.  I am curious of the Calc will drop when I add the mixture?  If so I can add some of the Calc portion of the two part to bring it back to a "balanced level."

 

Will be interesting to see what happens.