Possible issue with NaOH -based three part

[sculpin01]

Hi,

I have been using the sodium hydroxide high pH three part recipe for 6 months with really fantastic results in both growth and pH maintenance. Recently, I got a new shipment of NaOH (purchased off Amazon from Belle Chemicals, see link below) and made my standard mix (37.5% NaOH + Topic Marin Trace A-) for both of my tanks. My main tank is very well established and about 6 years old, with a second backup tank being 6 months old and flourishing. Within about a week, I noticed patchy areas of bleaching without frank RTN on some but not all corals in my main tank which uses approximately 5 cc of NaOH solution per hour. Subsequently, a few corals began to have significant tissue loss. I have sent off an ICP but that will likely take 10-14 days to get back. Initially the new tank showed no signs of this (dosed at approximately 1 cc/hour) but in the past few days it has as well. I am concerned that I got a contaminated batch of NaOH and am considering switching back to sodium carbonate, at least temporarily. If I do so, is there a one-to-one equivalence of sodium carbonate to sodium hydroxide, or will I just have to see where my alkalinity ends up? Also, do you have another source for sodium hydroxide as I am no longer trusting that which I purchased from Amazon?

Thanks,

Mike

 

[sculpin01]

Continuing this soliloquy,

With a 1:4000 dilution and a Hanna dKH tester, it appears that they are pretty close (sodium hydroxide to sodium carbonate), so I switched over to homemade B-ionic. Hopefully my pH won't completely crash.

 

[Maximitsurugi]

I run the same setup using Randy's high pH mix. I didn't used to get anything patchy but I put Trace A and K in the mix and the same thing you are experiencing started to happen. Some Acros looked like they had big bite marks on the plug, and the bases almost looked like they were stn'ing. I ended up redoing a mixture but this time without the A and K and it has stopped and started to regrow.

I think my Trace addition might have been too high. What I do now is I put 150ml of old two part into the 1300ml of new 2 part just to have some Trace in there.

 

[Randy Holmes-Farley]

Continuing this soliloquy,

With a 1:4000 dilution and a Hanna dKH tester, it appears that they are pretty close (sodium hydroxide to sodium carbonate), so I switched over to homemade B-ionic. Hopefully my pH won't completely crash.

I'm not sure exactly what you made or are switching, but my DIY recipe with sodium hydroxide has exactly the same alkalinity as my DIY recipe with sodium carbonate, but uses less mass:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

 

[sculpin01]

I run the same setup using Randy's high pH mix. I didn't used to get anything patchy but I put Trace A and K in the mix and the same thing you are experiencing started to happen. Some Acros looked like they had big bite marks on the plug, and the bases almost looked like they were stn'ing. I ended up redoing a mixture but this time without the A and K and it has stopped and started to regrow.

I think my Trace addition might have been too high. What I do now is I put 150ml of old two part into the 1300ml of new 2 part just to have some Trace in there.

As far as I can tell, it is elevated iodine from the A- solution that is affecting my corals. My iodine measured 426 µg/l vs normal seawater range of 66 µg/l after multiple 50-75% water changes. With the exception of barium and copper being minimally elevated, everything else was normal or even low, so I suspect that the K+ solution is generally fine.

 

[Maximitsurugi]

Did you fix the issue? I noticed after stopping the Trace mix I didn't get too many more issues but I started getting slower coralline growth so I tipped a little of the old mix into the new mix and started having burnt tips on a few acros. Specifically tenuis. Wonder if it's just coincidence or what.

@Randy Holmes-Farley How high of a pH is too high for a reef tank. I'd figured I'd have seen precipitation before any effect on Acros but maybe I'm wrong?

 

[sculpin01]

I definitely noted an improvement after stopping the A-. I kept K+ at half strength without any obvious issues.

I too wonder about how high a pH is too high. My pH electrode drifts extremely quickly when I use the NaOH 3 part and I get pH measurements of 8.7-9.0 a few days after recalibrating. Don't know if that is an issue with the electrode or related to NaOH.

Other issue I have run into is maintaining consistent dosing. I start getting back flow in my NaOH line after a few weeks due presumably to damage to the silicone tubing in the dosing head. My solution to this was to add multiple 3/16" PVDF check valves to the dosing line, but they also end up degrading over time.

 

[Maximitsurugi]

I definitely noted an improvement after stopping the A-. I kept K+ at half strength without any obvious issues.

I too wonder about how high a pH is too high. My pH electrode drifts extremely quickly when I use the NaOH 3 part and I get pH measurements of 8.7-9.0 a few days after recalibrating. Don't know if that is an issue with the electrode or related to NaOH.

Other issue I have run into is maintaining consistent dosing. I start getting back flow in my NaOH line after a few weeks due presumably to damage to the silicone tubing in the dosing head. My solution to this was to add multiple 3/16" PVDF check valves to the dosing line, but they also end up degrading over time.

I had that issue and Randy pointed me to irrigation fittings. I use the little black ones. They don't degrade with NaOH.

 

[sculpin01]

I had that issue and Randy pointed me to irrigation fittings. I use the little black ones. They don't degrade with NaOH.

Any chance you have a link?

 

[Maximitsurugi]

Anything that looks like that. Doesn't have to be the same but you want a snug fit. I like barbed so the don't pull out easily.

 

[Randy Holmes-Farley]

what.

@Randy Holmes-Farley How high of a pH is too high for a reef tank. I'd figured I'd have seen precipitation before any effect on Acros but maybe I'm wrong?

I wouldn't prefer my tank to routinely got above pH 8.6, but there's not a lot of evidence what happens there, aside from more abiotic precipitation of calcium carbonate.

 

[sculpin01]

Anything that looks like that. Doesn't have to be the same but you want a snug fit. I like barbed so the don't pull out easily.

I haven’t had a leak issue, just back flow through the peristaltic pump. Elevating the NaOH reservoir helps but I’m afraid to go to high or risk unintentional leaking.

 

[sculpin01]

I wouldn't prefer my tank to routinely got above pH 8.6, but there's not a lot of evidence what happens there, aside from more abiotic precipitation of calcium carbonate.

Any thoughts on how to modulate it? Dilute HCl or other mineral acid? I’d be leery of using acetic acid due to concerns of bacterial bloom.

 

[Randy Holmes-Farley]

Any thoughts on how to modulate it? Dilute HCl or other mineral acid? I’d be leery of using acetic acid due to concerns of bacterial bloom.

What is your pH?

Aeration will always bring it down if high, unless alk is exceptionally high.

A mineral acid will deplete alkalinity. Soda water can bring pH down in an emergency.

 

[sculpin01]

It currently reads 8.76 in one tank and 8.69 in the other, if you trust the pH probe. I calibrated it about 2 months ago. No definite evidence of unhappy corals with this, though.

 

[Maximitsurugi]

Well I'm between that and the A and K from tropic Marin that's causing burns for some acros. I'm going to get the probe to test pH soon so I'll have an idea. Randy. Im thinking I'll dose a part of my Alk with baking soda to sequester the pH at the level I want without issue. Sounds good? @Randy Holmes-Farley

 

[Randy Holmes-Farley]

It currently reads 8.76 in one tank and 8.69 in the other, if you trust the pH probe. I calibrated it about 2 months ago. No definite evidence of unhappy corals with this, though.

I'd recalibrate and see what you find. That seems too high to be accurate in any normal reef tank.

 

[sculpin01]

I'd recalibrate and see what you find. That seems too high to be accurate in any normal reef tank.

I agree. Not sure why it drifts so badly, though. Within 2 weeks of my last calibration, it had gone back to registering high. Could the NaOH be affecting the pH electrode?

 

[Randy Holmes-Farley]

I agree. Not sure why it drifts so badly, though. Within 2 weeks of my last calibration, it had gone back to registering high. Could the NaOH be affecting the pH electrode?

Not unless you are soaking the probe in the dosing solution.

 

[sculpin01]

Not unless you are soaking the probe in the dosing solution.

LOL. It's been a while since I worked in a lab but I haven't lost that much.