55 gal planted PH is rising, why?

[wetfarticus]

I have a 55 gal long planted tank. Its well established and been running for around 8 months. I do regular 50% WC every week. I use RO water and add minerals to adjust the GH/KH. I use Co2 and have a PH probe. Lately I have noticed my PH has been rising considerably. This is new as my PH is almost always between 6.8 and 7.0. Yesterday I noticed it had flew up to 7.3.
Ammonia 0
Nitrite 0
Nitrate 20-30 ppm
KH 5-6
Temp 76 deg F
I dose with PPS-Pro ferts
Also use flourish root tabs
I run an Aquatop CF-500 canister with UV
Also run an Aquaclear 110 HOB
I have no clue what might be causing this but it is very concerning as the fish I keep prefer PH levels at 6.7-7.0.

I need help. Anybody?

 

[Delapool]

Might be something in water added. Would you have readings for the re-mineralised water and no change in readings?

Also has the ph probe been calibrated lately and are the test kits still in date / not close to getting used up?

 

[TMaier]

The Kh additives will often increase PH.

 

[wetfarticus]

Might be something in water added. Would you have readings for the re-mineralised water and no change in readings?

Also has the ph probe been calibrated lately and are the test kits still in date / not close to getting used up?

I haven't recently calibrated the probe but it's readings are verified by the master test kit.

 

[wetfarticus]

The Kh additives will often increase PH.

True. But I mix my water in a barrel before hand. I run an air stone and circulation pump running in it for 24 hrs to make sure the levels are good. Then I add to tank and a couple days later the PH is climbing. I don't understand why.

 

[TMaier]

What's in your substrate and any rock in the decor? Or media in the filter?

 

[V227]

Wouldn't worry too much about the fish. As long as your water is pristine and kept at the appropriate temp, a ph of 7.3 is no big deal. Most aquarium fish are raised on farms, in mud bottom lagoons in Indonesia, Bangkok and Florida with little or no concern for PH adjustment. Unless your fish are wild caught, you are okay. If this situation persist, just add peat to your filter. Good luck.

 

[Delapool]

True. But I mix my water in a barrel before hand. I run an air stone and circulation pump running in it for 24 hrs to make sure the levels are good. Then I add to tank and a couple days later the PH is climbing. I don't understand why.

Do you test water for ph, kh, gh before adding? Is that still the same?

 

[Delapool]

I haven't recently calibrated the probe but it's readings are verified by the master test kit.

Ok. And when is the value of 7.3 recorded? Also how long is CO2 running?

Eg if CO2 was running all the time and starting water added hasn't changed, then I'd see if you added extra filter flow that might off-gas CO2 faster OR see if the CO2 bps rate has slowed down OR some combination. Depends if that value of ph 7.3 is influenced by the co2.

 

[Delapool]

What's in your substrate and any rock in the decor? Or media in the filter?

Good question as well!

 

[wetfarticus]

What's in your substrate and any rock in the decor? Or media in the filter?

I use CaribSea Eco-Complete substrate
I have rocks. Dont know what type they are. Got from my local aquarium store. Also have driftwood. Other than that it's planted.

 

[wetfarticus]

Ok. And when is the value of 7.3 recorded? Also how long is CO2 running?

Eg if CO2 was running all the time and starting water added hasn't changed, then I'd see if you added extra filter flow that might off-gas CO2 faster OR see if the CO2 bps rate has slowed down OR some combination. Depends if that value of ph 7.3 is influenced by the co2.

It takes about 2 days for the PH to rise to 7.3.

The Co2 system I have is automated. It is set to maintain a PH between 6.8 & 7.0. When the PH rises to 7.1 it releases Co2. If it falls below 6.8 it turns on the air pump.
So it is basically running non stop. The bps has stayed the same at around 1-2.

I'm going to try shutting down the HOB filter during the day while the lights are on. Hopefully that will do the trick. Hadn't thought about that. The return flow is probably releasing the Co2 much faster than before I added it.

I will let you know how it works out.

 

[wetfarticus]

Thank you all for the advice. Wouldn't have got as far with this aquarium without everyone on this forum.
I will try and remember to upload a photo.

 

[TMaier]

I use CaribSea Eco-Complete substrate
I have rocks. Dont know what type they are. Got from my local aquarium store. Also have driftwood. Other than that it's planted.

Rock can have a huge impact on water chemistry.

 

[V227]

If he did accidently purchase limestone from his LFS, I would think it to be a small amount only to raise his ph from slightly acidic to slightly alkaline.

 

[wetfarticus]

Rock can have a huge impact on water chemistry.

The rock has been in there since I set up the tank 8 months ago. This problem only started happening recently

 

[DpxNinja]

Don't make to much water changes 35% should be good if u do too much it might take beneficial bacteria away anyways hope this helps in a way

 

[wetfarticus]

Don't make to much water changes 35% should be good if u do too much it might take beneficial bacteria away anyways hope this helps in a way

I do 50% weekly. Too much?

 

[wetfarticus]

It takes about 2 days for the PH to rise to 7.3.

The Co2 system I have is automated. It is set to maintain a PH between 6.8 & 7.0. When the PH rises to 7.1 it releases Co2. If it falls below 6.8 it turns on the air pump.
So it is basically running non stop. The bps has stayed the same at around 1-2.

I'm going to try shutting down the HOB filter during the day while the lights are on. Hopefully that will do the trick. Hadn't thought about that. The return flow is probably releasing the Co2 much faster than before I added it.

I will let you know how it works out.

Ok. One day not running the HOB. PH = 7.45.
Co2 bottle is now empty. Not good. Using seachem flourish excel to maintain a somewhat normal PH.
This is starting to worry me.

 

[Delapool]

I'd cut back lights imo. Excel and CO2 injected are chalk and cheese ime.