help with chemistry

[albie611]

i just tested the water in my 20 gal (1st time in 3 weeks due to the holidays) and found that the alk and ph have both droped.
keep in mind that they have been rock solid for a long time and i cant figure out what happened. could it be the added growth of my stonies that did this?

nothing new added and no changes to the set up in months.

alk went from 8dkh down to 6
and ph went from 8.1 to 7.9
and the calcium did not change much.......was 480 now 460
water change is set for tonight and i will retest tomarrow.
what else should i do to raise both back to where they were ?

 

[reeferwanabe]

I'd have to say your on the right road to start with a water change and let us know what the readings are

 

[monsterfishkeeper]

Water changes

 

[Phyl]

Do you have 2 part on hand? If indeed you're starting to see growth on your stonie corals you're also going to need to start a supplementation plan, once you get things back up to par.