URGENT HELP

I came home to all the fish in my 55g hiding. i was like hmm..so i tested the PH it was below 5.0 did a 50% water change..today fish are still hiding my jacks were black now there pale..and i don't know what to do

open all your windows in that room and take any the top off the tank so it can get air and if possible pump some fresh air into the tank to raise th PH.

done dont know what the help happend

sometimes things just happen have you used any additives lately? some can cause the PH to crash I had my ALK on my reef crash from a solid 9 down to 6.
just give it some time and lots of outside air will do wonders.

also added some crushed coral into the gravel..now did not add anything before that

What was it before the crash?

nope striking just add it still there is some wierd behavior happening

I meant to say what was the PH before crash?

it was 7.0 dropped below 5.0

That is a pretty good crash.

Do you have very soft water? Softer water is much more prone to crashes then harder water due to the fact is has less buffering ability.

It could also be something as simple as a water change with water that was much lower in PH then normal (large amount of rain from water source ect.)

my tap water kh is 10 so i have hard water..there still behaving weird

Hmm well that kind of throws that idea out.
When was the last water change done before the crash and is the water currently coming out of the tap still at 7?

no tap is at 8.5 to 9 last change was about 3 weeks ago or more

Does your tap go down in PH if you let it sit over night? I know mine has some dissolved CO2 in it and out of the tap it is slightly higher then if I let it sit overnight and gas off giving me an actually reading.

You could also put some tap in a container with a lid and leave a little room for air and close it up. Give it a good shake and retest the water.

Might never know what happened but as we went over a little earlier a normal 'PH crash' happens when the buffering capacity of the water is used up. With a KH of 10 that is unlikely but not impossible. Over a long enough period of time enough acidity can build up in the tank to deplete the buffers and drop the PH sharply.

As Cwhip already said adding in some air to help get any dissolved gases that might be lowering it out of the tank can help and other then that you just need to water change back to normal. I honestly would say smaller frequent water changes might be your best bet. Slowing returning things to normal. A large water change that bumps the PH back up might be just as harmful as letting the fish sit in the lower PH for a few days. I might do something like 20% a day and give everything time to settle. This also would allow you to see if the PH was stabilized before changing it again.

Keep an eye of the ammonia level in the tank. At very low PH levels the bacteria that normally break down ammonia stop functioning as their normal level. The good news is ammonia is much less toxic at low PH levels so the fish would be ok until things got back to normal.

I hope the fish make it!

should i transfer the fish to my 75g?

I would just fight it out. Get things back to normal and hope that they all make it. Any change at this point will likely just stress them more. If you can get things back to normal at a decent speed they should bounce back. That is what I would do at least.

What kind of filtration do you have set up on your tank and how many fish including size do you have in the tank?

55g with penguin 350 hob with about 20 fish ranging from 4 inch to 1 inch

It seems like your crash was due to lack of filtration. Your last water change was over 3 weeks ago so your bio-load was unable to keep up with fish waste. You may also be feeding your fish 2-3 times a day which also adds to bio-load. This happened to me once when my tank was overstocked and i didn't do a WC on time. I added stronger canister filter and added some crused coral in the filter to help buffer the water as well as keeping the higher PH.

High ammonia drops the PH really fast and this is due to excess fish waste and excess uneaten food.

moved some of the acaras to my 75g the seam better today

I think , for my 2 cents , that a water change every 3-4 weeks is way to long between water changes !!! Once a week @ 25% is a much better regimen !!

difficult with a full time job 2 kids and five tank i tell ya..lol

I have 44 running tanks . I/we do water changes weekly , I work . Give me a different excuse . Your fish will Love you for clean water weekly . LOL