organic waste question

[arowfan]

so i decided to check the ph in one of my tanks the other day and noticed that it was at about 6.0! i then checked the water out of the faucet and it was at 7.4ish! so far, over the past 3 days i've broken the 75 gal tank into 3 section, each day really cleaning the gravel in that section, with about a 20% water change; today the ph is at about 6.6...
is this the best way to get at this problem? i decided to check the ph because of a dorado i recently purchased has not been eating- and the owner told me to check the ph because of a possible orgaic waste buildup because they are a voracious fish
should i just do a 20% change every day until better or give it a day to settle then get back at it tomorrow?
thanks in advance!

 

[12 Volt Man]

you should be able to do a 15-20% WC each day with no trouble.

the question is did you pH drop from actual fish waste/rotting food or was it tanins from driftwood in your tank?

its generally one or the other (or both)

 

[arowfan]

hey 12 volt, it had to be fish waste, don't have anything in there that would lower it like driftwood.

so by doing these water changes, am i removing large quanties of good bacteria or it should be ok?
thanks again =)

 

[12 Volt Man]

you should be okay as long as you are not rinsing your filter too.

just do some water changes a little each day for a bit until the pH gets up close to tapwater pH. make sure to use your dechlor as usual.

good luck

 

[arowfan]

forgive me, but whats dechlor? is that like cycle or stress coat?

 

[12 Volt Man]

dechlor is any dechlorinating solution, such as Prime by SeaChem, AquaPlus by Hagen etc.

it removes chloramine and chlorine from your tapwater. you generally add it to the tank before you put the new tap water back in.

 

[arowfan]

what if i have well water? then i won't need that then right?

 

[TwistedPenguin]

Right, you won't need it with well water if it's your own well and no one's put bleach down there. I've got well water also and use it straight out of the tap untreated.
Well water is normally hard and very stable. It sounds like you might've gotten lax on water changes for the pH to crash like that. Is that what happened?

 

[arowfan]

yep thats exactly what happened! wasn't doing them that often, so i have myself to blame!
thanks guys =)

 

[12 Volt Man]

ahh.. classic 'old tank syndrome'

glad to hear you got the problem identified.