Help, ph 8.6!

[draend]

Hi, just did a test and my PH has jumped to 8.6 an alk has fallen a slight amount. all else still looks ok, nitrates 0-5 nitrite 0, temp 78, sg 1.025, ammonia 0
just recently changed to MH an having a ton of bubbles an algea bloom, maybe the cause? anything i can do to quick fix? obviously water change coming soon as is ready.

 

[apos]

The bloom could be what's doing it I think: plants photosynthesizing raises the ph, right? If so, you cut way back on your light that could help drop the ph. How long do you have your MH's on for? Hopefully not all day long. I've never used MHs, but I've heard that you have to break the tank into them very slowly.
I also know there is a product called ph down, but I'm not sure how safe it is in a reef tank. Whatever you do, make sure to do it fairly slowly, bit by bit over time instead of dumping a full dose of ph down or something in all at once.

 

[earlybird]

What are your levels for calcium, alkalinity, and magnesium? My guess is they are out of whack. Are you dosing anything at all (kalk, purple up, 2 part)? What kind of sand do you have and what is your water source (well, RO, tap)?

 

[ophiura]

I would personally not recommend anything drastic to lower it, as it will naturally fall over time. Rapid changes can be more harmful than a natural course at this point.

 

[draend]

Thanks all for info, am not going to do too rapid of water changes, about 5% every 4 days till it lowers, not to drastic is it? also, have 110 lbs of live sand? carrib sea live sand i think it was called, didnt test for magnesium, alk an calcium were good, calc a lil high i think, 480 and have my mh on for 9 hrs, too long? Thanks again for all the info ph down today to 8.4 after the water change, an snails are workin soooo great on algea