Dosing Baking Soda and my RBTA deflated

StlSalt · Oct 30, 2020

So since I set up my sulfur denitrator my Alk has been dropping. It finally got down to 6.1 DKh so I read up on dosing baking soda to raise my Alk. To start I'm just trying to get it to 7 so I used a Supplement calculator and found that to raise my Alk to 7 I need 7grams of Baking Soda. I filled a soda bottle with 16 ounces of RODI water and dissolved the 7 grams of B.Soda in the water. Then I drilled a hole and stuck some air line tubing through the cap. I sealed that up and put a valve on the other end of the ail line tubing. So basically I have an IV bottle that I have hung above the tank. I'm dripping at about 1 drop per second in front of a powerhead near the top of my tank. My RBTA is indirectly in the flow and it just deflated in about 10 minutes. I know nems can be sensitive, and I think it will be fine but I need to keep dosing and don't want to keep doing this to the nem. Is my mixture too strong? I don't have a sump so that is not a solution, I have to drip into my DT.

edit LOL at the word filter changing B.S. to crap.

Ron Reefman · Oct 31, 2020

I have 35 RFAs, and both a curly-Q and a BTA all in a 16g tank with a HOB filter and an in-tank skimmer. I dose alk from 7.0 -7.5 dKH up to 9.5-10.0 dKH every week. I use soda ash (very similar to baking soda) and dose 60 ml (Randy's Recipe 2) all in one dump into the tank. None of my anemones even flinch.

StlSalt · Oct 31, 2020

Ron Reefman said:
I have 35 RFAs, and both a curly-Q and a BTA all in a 16g tank with a HOB filter and an in-tank skimmer. I dose alk from 7.0 -7.5 dKH up to 9.5-10.0 dKH every week. I use soda ash (very similar to baking soda) and dose 60 ml (Randy's Recipe 2) all in one dump into the tank. None of my anemones even flinch.

WOW! That's wild. I thought you weren't supposed to go up more than 1dKH per day.

My BTA deflated faster than I've ever seen it deflate. It's better this morning, I figured it would be I've had it for a few years. I have 2 RFAs and they didn't flinch either. I wonder if I should switch to soda ash it's not supposed to be as harsh and it's not supposed to lower PH. Since I had baking soda I figured I'd try it. My Alk was at 6.9 dKH this morning so it still needs to be raised.

So you're probably going to tell me it's okay to raise my alk again today instead of waiting a day and raising it some more on Sunday, correct?

Ron Reefman · Oct 31, 2020

StlSalt said:
WOW! That's wild. I thought you weren't supposed to go up more than 1dKH per day.

My BTA deflated faster than I've ever seen it deflate. It's better this morning, I figured it would be I've had it for a few years. I have 2 RFAs and they didn't flinch either. I wonder if I should switch to soda ash it's not supposed to be as harsh and it's not supposed to lower PH. Since I had baking soda I figured I'd try it. My Alk was at 6.9 dKH this morning so it still needs to be raised.

So you're probably going to tell me it's okay to raise my alk again today instead of waiting a day and raising it some more on Sunday, correct?

That's right. But I'd try to dose it away from the BTA.

I have a 90g DT that is 60% zoas, 20% lps and 20% sps. I also have fish, shrimp, clams, urchins, sea cucumbers, sea stars and more in the tank. I test every Monday and my Ca & alk typically run 380ppm to 400 ppm for Ca and 6.0 to 6.5 dKH for alk. I dose Randy's recipe 1 Ca and bring it up to 425 ppm and Randy's recipe 2 alk and bring it up to 9.5 or 10.0 dKH which is over 400 ml in one shot. Yes, my sps don't like the big alk dump from 6.0 dKH to 9 or 10 dKH. They retract their polyps for all of 2 to 4 minutes and then life goes back to perfectly normal and everybody has polyps out.

I used to use a doser and dripped Ca & alk. The doser I had was great and dosed a very small amount every 10 or 15 seconds 24/7. It did bring my pH up about 0.1, but it's quite temporary. Which is why I used this doser. But keeping it running smoothly became a bigger problem than it was worth. So I started dosing manually.

I should probably switch to a twice a week manual dosing so I dose less and keep parameters more stable. But honestly, I've seen almost no negative response that lasts longer than just a few minutes. And everything grows fine.

StlSalt · Oct 31, 2020

Thanks for the input, I don't do SPS but I have some softies and LPS, a clam. For now I'll do small doses and try to stay away from the BTA's side of the tank. Oh here's my high tech dosing pump. Thank God gravity is still free.

Ron Reefman · Oct 31, 2020

Mine was a 2 line medical grade pump. When it worked, it worked great. When it went off, it was a PITA! Clogged lines, silicone tubes worn through, some power failure issues before an upgrade. Manul is just easier for me. But then I'm retired so I have the time.

Randy Holmes-Farley · Oct 31, 2020

I’m not sure if the dosing was the cause, but it is always best to dose anything away from organisms.

StlSalt · Oct 31, 2020

Randy Holmes-Farley said:
I’m not sure if the dosing was the cause, but it is always best to dose anything away from organisms.

I do have a question for you. Why does my sulfur denitrator reduce my Alk? What's the chemical reaction in play there?

Randy Holmes-Farley · Nov 1, 2020

Nitrate in the Reef Aquarium - REEFEDITION

Nitrate is an ion that has long dogged aquarists. It is typically formed in aquaria through the digestion of foods, and in many aquaria it builds up and can be difficult to keep at natural levels. In the past, many aquarists performed water changes with nitrate reduction as one of the primary...

www.reefedition.com

8. Sulfur Denitrators

In these systems, bacteria use elemental sulfur and produce N2 from the sulfur and nitrate according the following equation (or something similar):

2 H2O + 5 S + 6 NO3– → 3 N2 + 5 SO42- + 4 H+

The production of acid (H+) in this reactor can tend to reduce the aquarium alkalinity. It has also been suggested to pass the effluent of such a reactor through a bed of aragonite to use the acid (H+) produced to dissolve the calcium carbonate, and thereby provide calcium and alkalinity to the aquarium. While that is a fine idea, it doesn’t add much calcium and alkalinity to most aquaria.

To estimate the magnitude of the effect, we start with a liberal estimate of how much nitrate might be removed. Say 10 ppm of nitrate per week.

10 ppm nitrate = 0.16 mmole/L of nitrate

Since 4 moles of H+ are produced for every 6 moles of nitrate consumed, this will produce

0.107 mmoles/L of H+ per week

How much calcium this could produce?

Assume that it takes one proton to dissolve one calcium carbonate:

CaCO3 + H+ → Ca2+ + HCO3–

Clearly, this is a substantial overestimate because much of the acid will be used up driving the pH down to the point where CaCO3 can even begin to dissolve. Consequently, we have an upside limit of 0.107 mmoles of Ca2+ per week. Since calcium weighs 40 mg/mmol, that’s 4.3 ppm Ca2+ per week.

For comparison, an aquarist adding 2% of the tank volume in saturated limewater daily is adding on the order of 16 ppm of calcium per day. Consequently, this method may not be especially useful for maintaining calcium. Additionally, the acid produced will have a long term lowering effect on the alkalinity. In fact, it is double dipping on the alkalinity depletion since alkalinity is consumed when the nitrate is produced, and again when it is removed in the denitrator. So if you use a sulfur denitrator, be sure to monitor the alkalinity in the aquarium.