Alk!!!

[Dave3112]

Ok, so I have been dosing BRS 2-3 part for a while now. I have been considering a CA reactor because I dose 300ml/day but that is another post......I have always used the soda ash for the alk because I like the boost in Ph but lately I can't keep the alk stable. I test daily now and in the mornings it is 7.5 so I bring it up to 8.5 and dose the 300ml by the dosers. Well by the next a.m. it is back at 7.5!!! After a week of this and my acros looking like crapola I started using the sodium bicarbonate (bought it from BRS by mistake) and now the alk is finally starting to stabilize at 9 again. It sounds crazy to me so I was wondering if there is a chemical reason why bicarbonate (baking soda) is stable for my system while carbonate (soda ash) is not?

 

[ronnie]

What is your magnesium? Low Mg will cause fluctuations in your Ca and Alk pretty severely.

 

[Dave3112]

I guess I should give the rest of the system info

220 display with frag tank and sump/fuge plumbed together (~280 gallons total) fuge has cheato and on reverse light cycle.
PH 8.33-8.42
Alk used to be rock steady see above for what it is now
Ca 420
Mg 1500-1550
PO4 undetectable (I run GFO and Carbon in a BRS dual reactor and change both out monthly)
Nitrates were undetectable last time I checked, 2 months or so ago.

I use Elos test kits for everything. I bought a Salifert Alk test kit when this started to double check the Elos and they were the same.

 

[Dave3112]

What is your magnesium? Low Mg will cause fluctuations in your Ca and Alk pretty severely.

Thanks Ronnie! That is what I thought at first but my Mg stays at 1500-1550.

 

[ronnie]

I wonder if you got a bad batch of Soda Ash? Was it a new bag/box/container of ash?

 

[VegasRick]

Are you baking the soda ash to drive off the co2? might make a difference, also storing in an air tight container

 

[Dave3112]

Actually it was pretty new "jug" of the stuff. But I believe I had been using it for about a month. Maybe not. I use so much of the stuff. LOL. But I bet that could be it.

 

[Dave3112]

Are you baking the soda ash to drive off the co2? might make a difference

Why would you bake the soda ash? I never have before. I thought thats what you did for the sodium bicarbonate to make soda ash. Right? Or do I have it mixed up? LOL. That happens to me sometimes.

 

[VegasRick]

maybe i have it backwards

 

[Dave3112]

maybe i have it backwards

Man. I am confused now. LOL. gotta check the RHF 2 part instructions real quick to make sure. :bigsmile:

 

[Dave3112]

Yeah you bake the baking soda to make soda ash. Whew. you got me confused, as if I'm not already!! LOL! Thanks for the reply VegasRick!

 

[ronnie]

You bake bicarbonate to make soda ash (i think!)

Missed pg 2! LOL

 

[VegasRick]

Not surprised I had it backwards. I have never done the DIY version. Only time I ever use 2 part is on quarantine system and I use pre-made stuff. I just remember you had to bake it to drive off co2 and keep it airtight so it doesn't absorb co2 back in.

 

[Dave3112]

Thanks Rick and Ronnie for the replies. Anyone else got a guess?