Low alk and pH

[das75]

With a hagen kit measured KH at 70 ppm and pH at 7.9 (confirmed with LFS Pinpoint) and no reading for Ca.

Tank is 75g, no sump, internal skimmer, 4" DSB, FOWLR (with few small button sized anemones), 2x40W NO fluorescents. Using store bought ro/di and adding no supplements. Have a bit of a hair algae problem, mostly back wall and coralline growth stopped few months back. Tanks been up for ~15 months.

Was looking into something like a 2-part for raising Ca hoping coralline would out compete the hair but realize water parameters need adjusting first.

When first setup the tank was using treated tap water (Cycle) but started to get cyano. pH was 8.0 - 8.1 and Ca mid 300's. After the switch to ro/di cyano stopped, Ca and pH dropped and hair algae took off.

Questions:
- using IO salt, can this salt be used without Ca supplement
- what about going back to tap water for some trace elements and buffering capacity
- if I continue with ro/di, should I buffer with baking soda before adding salt?

 

[randy holmes-farley]

No calcium means what? That you never saw a color change, or that it changed before you added any titrant? Most likely the former, and you need to add more titrant.

what about going back to tap water for some trace elements and buffering capacity

A bad idea, IMO. Here's this months article on tap water:


http://www.advancedaquarist.com/issues/jan2004/chem.htm


using IO salt, can this salt be used without Ca supplement

Well, you'll need a calcium supplement for the tank anyway, so using a salt mix with low calcium just adds to that. I use IO myself.

if I continue with ro/di, should I buffer with baking soda before adding salt?

No. I'd suggest that you pick a balanced calcium and alkalinity supplement as described in this article:

How to Select a Calcium and Alkalinity Supplementation Scheme
http://www.advancedaquarist.com/issues/feb2003/chem.htm