pH keeps droping

[fishnut]

all the water parameter in my 20 and 40 gallon tank are good but the pH keeps droping and there is no driftwood or any substrate to lower the pH.
Tap water pH is 7.2-7.6 which is perfect. I just did not measure the kH and gH.

Both tanks goes from 6.8 and goes down to 6.0 in a few hours. Both tanks have been set up for 2 weeks and I only have 5-6 small plecos. I would do a water change to bring the pH up to 6.8 and next morning the pH would go back down to 6.0 again.

I tore down the 20 gallon and did a 100% water change using tap water and had it ran for 1 week without fish and the pH is still 6.0.

I can not figure out what I am doing wrong since both tanks are not overstock. My 180 gallon is overstock and the pH is always stable. All my other tanks use the same tap water during water change and are fine.

 

[haynchinook334]

add some chunks of of coral or mix some crushed coral to your tanks substrate. this should raise your PH.

 

[Bderick67]

Need to wait until the tanks are cycled before worrying about the pH levels.

 

[TwistedPenguin]

Without knowing your kh and gh it's like buying shoes without knowing what size you wear. It sounds like your kh is extremely low though. If it's dropping that much I probably would be inclined to add some crushed coral to buffer it so it'll resist crashing if it were me. But most important is getting a kh/gh test kit (API is best, not strips) so you know where you stand. You can't 'fix' something if you don't know what you're 'fixing'.

 

[Lupin]

Measure your KH and GH, post the exact species of your plecos and sizes, then feeding schedule and other water parameters. Those are equally important.

 

[fishnut]

Need to wait until the tanks are cycled before worrying about the pH levels.

why do you think the tank is not cycled? I treated the water and used the bio media from my existing wet/dry from another tank. If the tank is not cycled and I add fish, I am sure pH will not be the only thing that fluctuates.

 

[fishnut]

Without knowing your kh and gh it's like buying shoes without knowing what size you wear. It sounds like your kh is extremely low though. If it's dropping that much I probably would be inclined to add some crushed coral to buffer it so it'll resist crashing if it were me. But most important is getting a kh/gh test kit (API is best, not strips) so you know where you stand. You can't 'fix' something if you don't know what you're 'fixing'.

I did not measure the kH and gh because I use tap water to do water change in my other 11 tanks and they are fine. I only have trouble with my 20 and 40 gallon, the other tanks ranging from 55 to 300 are fine.

 

[fishnut]

Measure your KH and GH, post the exact species of your plecos and sizes, then feeding schedule and other water parameters. Those are equally important.

in my 40 gallon breeder, I have 4 adult zebra plecos and a few ghost shrimps. I do not feed them much because I did not want to make the water any worse. For feeding, I only throw in a couple of earthworm sticks.

As for water parameter,
NH4= 0
no3=0
no4=0

I did water change last night and the pH was 7.2. This morning it was 6.8 at 7 am and at 5 pm, it came down to 6.0.

 

[Lupin]

why do you think the tank is not cycled? I treated the water and used the bio media from my existing wet/dry from another tank. If the tank is not cycled and I add fish, I am sure pH will not be the only thing that fluctuates.

Bderick has a valid point. You mentioned both of your tanks are only two weeks old. This does not imply your tank has finished cycling. In fact, the water parameter results you released showed there is a possibility either your tank never cycled at all or your tank is only too heavily planted with few fish and less feeding thus nitrates are consumed rather quickly.

in my 40 gallon breeder, I have 4 adult zebra plecos and a few ghost shrimps. I do not feed them much because I did not want to make the water any worse. For feeding, I only throw in a couple of earthworm sticks.

As for water parameter,
NH4= 0
no3=0
no4=0

I did water change last night and the pH was 7.2. This morning it was 6.8 at 7 am and at 5 pm, it came down to 6.0.

I did not measure the kH and gh because I use tap water to do water change in my other 11 tanks and they are fine. I only have trouble with my 20 and 40 gallon, the other tanks ranging from 55 to 300 are fine.

How will you determine the cause of your pH drop if you are not measuring your KH and GH? Did you use crushed corals, crushed oyster shells or any other buffers at all in your other tanks? If so, that would explain the pH stability.

 

[fishnut]

I treated the tap water going into the 20 and 40 gallon tank and use the bio media from another established filter and had it ran for a week to 2 week before adding any fish.

I do not use any additive or addition to increase the pH and I keep mostly south and central american fish.

The reason that I do not measure kH and Gh thinking that if kH and Gh are low, then my other tanks would have the same problem too.

I just measured the KH and Gh from the tap tonight and they are 120 and 150 respectively. But the reading from the tank are 40 and 50 respectively.

I added some crushed coral to both tanks after water change and the reading is curently 7.2 after 1 hours from the water change.



As for the tank being cycled, I am using existing bio media from an established filter, had the tank ran from 1-2 weeks before adding fish in and both tanks are not over stock. I am really baffled as to why my pH crashed.