pH keeps going down

[paddy]

Hi all,
I had a beautiful red oscar for 2 years, but then lost her during a change to a new, larger tank.

Since then, I have added a 10 and a 20 gal tank in addition to the 55gal. I've been having severely acidic water problems. Tap water registers 7.6, but the tanks always drop down to 6.0 with time. Other water values like Nitrite, Nitrate, hardness, chlorine, ammonia are fine.

What is causing the pH to drop so far down? I have fancy guppies in the 2 smaller tanks and a baby oscar in the large 55gal. Filters are changed at least monthly, ~25% water change every month. The guppies are dying. So far the oscar is ok, but I'm worried.

 

[Floyd R Turbo]

Well, there could be many factors. Overfeeding and inadequate water changes would be the first thing that comes to my mind. With oscars especially - which are very dirty fish - you need to be doing at LEAST 25% weekly, if not 50%. That will keep the higher pH water in there on a more current cycle. Second, watch your feedings and do a lot of gravel vaccumming to clear excess waste. Third, review your filter setup and cleaning schedule. Is it enough filtration and is it cleaned often enough? Etc

 

[blue71]

if you have a filter you can put your own media in i would put some crushed coral in a filter bag or pouch as it will serve as a bufferer.

 

[paddy]

Thank you for the replies! Here's a bit more info about the tanks.

The 10 gal with female guppies has a small 5-15 gal Whisper filter. The 20 gal with male guppies has a 30 gal Whisper filter. I'll try suctioning the gravel more often for these. The filters components are cleaned when there is a decrease in water flow or 1x/month.

****Can coral be placed in a freshwater tank? If so, I'll add it.

The 55gal tank has 2 filters - 60gal TopFin (like a Penguin) and a 55gal Aqueon. There is only a small amount of gravel in this tank since Oscar's make a mess of it anyway. There is also a 2yo common pleco in the tank. He has a slate hide-a-way.

All three tanks have a green plant that I got as a beginner. I don't know what it is, but it can survive without being rooted in gravel and it prefers low light.

 

[Blueiz]

I think before you add crushed coral to your tank to raise the ph, you need to find out why it is falling to begin with.

How long does it take for the ph to drop from 7.6 to 6? What is your partial water change schedule?

 

[blue71]

If it is all the tanks not just one, than it is your water, also are you adding aquarium salt like you should be? How often do you do water changes? You should be doing at least 25% weekly.

 

[blue71]

Also, on the 55 gallon, I don't think that that is enough filtration I would go with a canister or an Emperor 400, It is really worth the money.

 

[joy13]

First thing is to test your water from the tap and then test it again after letting it set for 24 hours. Some cities use buffers that will cause problems with ph.

There really isn't any reason to add salt to an other wise healthy aquarium for ph problems. It can actually cause more problems.

A lot of people with African cichlids will use crushed coral for a substrate, so you can add crushed coral.

If your tanks are planted are you using CO2? A decrease in oxygen can make the ph drop.

A good rule of thumb is to change about 10 to 25% of your water weekly. If there are any fish deaths do it right away since the ammonia can spike. I will do one the day the fish is found dead and then a couple of smaller ones for a few days.

If your plecos aren't getting enough to eat they will suck slime coat off your fish and will cause them to die.

 

[paddy]

Well, you are all making me think a lot . . .
The pH problem is in all 3 tanks. I don't know how long it takes the tap water to drop from 7.6 to 6.0, I'll need to check that.

I vacuum the 10 and 20 gal tanks weekly with about 3 - 5 gal of water removed and replaced at that time. It would be no major problem to increase the amount of water.

The 55 gal I vacuum 2x/week, taking maybe 5 - 7 gal of water out and then replacing it.

All 3 plecos (1 per tank) have nicely rounded bellies, so I don't think they are short on food.

I do add salt to all tanks, carefully following directions and erroring on the side of too little if there is any question of amount. If I don't have salt available (for some odd reason), then I use APIs StressCoat+

All tanks have this green plant in them. It does grow, although it is not rooted in gravel. I have never been advised by local Pet shop/aquaria shop people to use CO2. How is that done?

All of these responses have made me realize that I haven't been very scientific in my approach to the aquaria. I'll need to change that.

 

[Blueiz]

There is no need to add salt to your water unless treating for a disease or combating nitrITE toxicity.

Since the prob is in all 3 of your tanks, most likely it is your source water. Joy13 gave some excellent advice, test your water from teh tap, then again after it has sat out for 24 hours.

Adding CC into your tank, whether it be a small amount in your filter, in a media bag hanging in your tank, or as a substrate will keep your ph up in the neutral range.

With your set up, you don't need co2 for your plant. There are a lot of factors to consider when adding co2 to your tank, such as the lighting, type of plants, fertilizers to add, and what your goal for a planted tank is.