High alk - time bomb?

[karburn]

I just picked up a new account for the maintenance biz (yea!) and itââ"šÂ¬Ã¢"žÂ¢s an interesting situation. A 75-gallon reef with a small assortment of softies and a couple of fish (not the problem). The Ca tested at 170, Mg is 870 and the pH hovers around 8.05 (on my meter) and the alkalinity is a whopping 5.7 meq/Lââ"šÂ¬Ã‚¦.at least thatââ"šÂ¬Ã¢"žÂ¢s as high as the Salifert test kit goes! Heââ"šÂ¬Ã¢"žÂ¢s been using a well-known granular Ca additive (Ca chloride) and itââ"šÂ¬Ã¢"žÂ¢s counterpart dry ââ"šÂ¬Ã…"œsuper bufferââ"šÂ¬Ã‚, plus an occasional dose of kalk. With this much alkalinity, itââ"šÂ¬Ã¢"žÂ¢s tempting to add the granular Ca at the rate of 2 ââ"šÂ¬Ã¢â‚¬Å“3 teaspoons per day until we get back up to snuff. However, the specter of the dreaded ââ"šÂ¬Ã…"œsnowstormââ"šÂ¬Ã‚ looms large, so I want to be careful. Would a better course be to use Ca Hydroxide (pickling lime in laymanââ"šÂ¬Ã¢"žÂ¢s terms) dosed daily to boost not only the Ca but also the pH until we get back into the 400ââ"šÂ¬Ã¢"žÂ¢s on Ca? With the pH meter I can monitor the dose so as not to exceed a .2 bump in pH at one time. Always looking for that second opinion!

I'll keep the Mg @ 3X Ca as we go.

Thanks as always,

Kevin A

PS: That sarcophyton is almost 100% recovered. Amazing. Glad I did not divide it yet.

 

[Anthony Calfo]

Cheers, Kevin

Excellent to hear about the leather.

Regarding the high ALK... please do not add any chemicals whatsoever to correct it. Too precarious/dangerous... and it will not correct all skewed parameters from the stray, just the ones you can conveniently test for.

The low Ca is good and expected with the high ALK. Yin and Yang to some extent naturally. Aquarists get themselves in trouble from trying to make both high simultaneously.

My strong advice is to do 2-3 large (50%) water changes in the next 10-14 days to dilute and reconstitute the water quality to a more even keel. Test then and if it is in a sane ballpark, then tweak with supplements.

Frankly, I'd prefer you did only water changes to get back on par for this system (the best way IMO).

With w/c's though... the correction will be simple enough. Its the same old saying over again:

Dilution is the solution to pollution

Kind regards, Anthony