pH Drop with Water Change / Gravel Cleaning

[Panda1]

Please Help -- At a loss to understand pH drop after water change
I am a newbie to fish keeping & am experiencing a pH drop when I change (and clean gravel) approximately 20% of my aquarium water. My aquarium has been set up for 4 weeks and is still cycling.

Question: What is causing the drop in pH after water change & gravel cleaning?
Is it contaminates in gravel?
Not adding Seachem Neutral Regulator to make-up water?
Please help as I am at a loss to understand the pH drop.

My current aquarium water chemistry reading as follows:

pH (before water change) = 6.9 as measured by PinPoint meter & Aquarium Pharmaceuticals liquid test kit
Ammonia = .25 ppm
Nitrite = 1.5 - 2.0 ppm (currently in Nitrite spike of cycling)
General hardness = 143
Water temperature: 78 F
Alkalinity: Unknown â?? Need to buy test kit

I measured the pH of the new water (with Pinpoint meter & test kit) I added to the aquarium & it measured approximately 7.2. The other readings as follows:

Ammonia = .25 ppm
Nitrite = 0 ppm
General hardness = 143

I treat the make-up water with AmQuel (rate of .5 ml per gallon) + and let stand for 24 hours before adding to aquarium.

After I add the make-up water, within hours the pH drops to 6.2 - 6.3 every time. In approximately three days, the pH slowly returns to 6.9

When I first set-up the aquarium, I added Seachem Neutral Regulator (7.0) to the water. I have not added this product to the make-up water.

As to fish I have in a forty-one measured gallons (tank trade-stated size is 49 gallon) aquarium as follows:

4 Panda Corydoras
3 Ottos
6 White Clouds
1 Betta

I do not have live plants nor use CO2 injection.

The make-up water was tested after it was in a plastic (new) bucket for 24 hours.

My best "guess" is that due to my lack of experience & control in feeding the fish and resultant increase in biological waste has created an acidic gravel base. When I clean the gravel, I may be releasing acid trapped in the gravel. Is this likely or even possible?

Would adding the pH neutralizer to the make-up water help?

Thank you,
Panda

[Barbie]

Could you test your kH for us, also? That is going to tell us the buffering capacity of the water, or the ability for it to keep the pH stable, basically. You don't mention, but are there fish in your tank now? Do you have plants? or CO2 injection? Sorry to just answer your questions with more questions, but it will help us, help you. It sounds like your water is pretty soft, but the neutral regulator you added at first may be still acting to buffer the water back up to as close to neutral as it can. When you tested the new water, was that out of the tap? Or in the bucket just before you aded it to the tank?

Barbie

[Panda1]

Hello Barbie,

I currently do not have a kit that measures KH. I will pick one up on my next visit to the petshop.

As to fish I have in a forty-one measured gallons (tank trade-stated size is 49 gallon) aquarium as follows:

4 Panda Corydoras
3 Ottos
6 White Clouds
1 Betta

I do not have live plants nor use CO2 injection.

The make-up water was tested after it was in a plastic (new) bucket for 24 hours.

My best "guess" is that due to my lack of experience & control in feeding the fish and resultant increase in biological waste has created an acidic gravel base. When I clean the gravel, I may be releasing acid trapped in the gravel. Is this likely or even possible?

Would adding the pH neutralizer to the make-up water help?