dosing baking soda to raise alk

[SneakyPete]

Hello all.

So I did some water tests today and my PH was 8.4, which is in the ok zone, but the high end, but my alk was at 7.5 or so. My test goes from 7 to 8. It turned slightly yellow at 7 and completely yellow at 8, so probably 7.5.

Anyway, i've read that the best way to raise alk without affecting your PH too much is to use baking soda. According to a chart (i'm assuming I have 40g between my dt and sump in a 40b with 29 sump), i need to add roughly 2.4 tsp of baking soda.

I obviously don't want to do that all in 1 shot, but what's the best way to dose that? Can I throw a tsp into 3.5g of ATO and just let that run over a week or so?

[MARINECRITTERS]

2.4 tsp dissolved in water really is not that much, you can add it in through a drip line.

Bake the baking soda in the oven at 300F for an hour or so, it will become more effective and have less of an impact on the pH.

[triggreef]

Keep in mind using baking soda will cause Ca to precipitate slightly. I used it for that sole purpose once when I had Ca way too high and it brought it down fairly fast.

[SneakyPete]

2.4 tsp dissolved in water really is not that much, you can add it in through a drip line.

Bake the baking soda in the oven at 300F for an hour or so, it will become more effective and have less of an impact on the pH.

I will be sure to bake it first.

So if I add like 2 tsp to my top off and just add it that way over like a week, there should be no issues? My top off pump is an aqualifter and runs for about 15 minutes on a timer. That shouldn't be an issue, right?

Edited to add, i'll do a ca test here too in about a half hour.

Ca is at 420-440. According to the chart, 430 is pretty ideal, so that should be good there. Hopefully it doesn't precip too much out.

[Im14abeer]

In your case, you probably don't want to bake the baking soda. Baking it drives off some of the CO2, raising its pH. Adding raw baking soda actually has a slight lowering effect on pH. You should note that baking baking soda raises its solubility, making it more potent. So if you used a calculator to determine how much to add, you need to be sure which product you're working with.

For reference:

http://www.reefkeeping.com/issues/2006-02/rhf/

[Shaummy]

You can put it in ATO..however there are a couple of caveats.. If you are using straight RODI for top off, you can mix it in there BUT if you are already using something like kalk in your ATO, then the addition of the the baking soda will likely cause a precip even in the ATO container and cause a huge mess.

That said, mixing it into your ATO, may or may not dose the correct amount that you need daily to stabilize you Alk numbers.

In my case I top off about 1 gallon a day and have kalk mixed in, so I make up a separate baking soda solution and drip that in.

Due to the inconsistency of ATO..I'd find a way to dose it (container and drip line) or you can try to dose by hand in small amounts. When I first started I used a syringe to add 5ml or so to dial in the amount I needed to add every day.

[SneakyPete]

I was doing some reading last night and agree @Im14abeer, I probably don't want to bake it as my PH is already a tad bit high. And thank you for the link. I'll read through that here this weekend. I don't have enough stony corals that I ever have low calcium, but I hope to someday, haha. I have a magnesium test on the way and will do a test soon.

@Shaummy
I don't dose kalk yet, but I plan to in the near future to try to maintain my levels. But you are probably right, a drip line would probably be better. I plan on modifying a soda bottle with a medical drip line and will probably use that to raise my alk up to the proper level and then hopefully to keep it there.

[dyazdani]

Correct, just use straight baking soda with your pH of 8.4. You should end up in just the right spot.

[disc1]

Edit:

[swcc]

http://www.reefkeeping.com/issues/2004-12/rhf/... Another good read.