hard water mystery

[dana]

Hello,

I have a 55G fresh water tank. Up and running for over a year.

Current fish: 6 small/med angelfish
3 cories
1 BN pleco
4 Emperor Tetra
3 Serpae Tetra
Maybe 1 upsidedown catfish--I rarly see him!


I plan on getting a new tank soon and moving the tetras and building proper schools of them and the cories.

Anyway, my problem: my tank water is VERY HARD. My tap water that I use to fill my tank is VERY SOFT. I use filtered rain water, from a cistern. It is safe, we drink it and it is occasionally tested. Every thing I have in my tank is freshwater aquarium approved. I have tanish gravel, a few fake plants, and a few plastic fake logs. The aquarium water has always turned hard. I do not add salt or anything else to the water. I tested the gravel and one of the plants in a seperate bowl, after two weeks the test water is still soft.
I do regular water changes, about 15G a week, broken up into two changes. I vacuum the gravel. I use to do larger water changes (15-20G at one time), but I had fish dying. I have good filtration, bio wheel with two filter pads. I have a airstone strip.

Here is the tank--I use the API test tube test:
Ammonia: 0
Nitrite: 0
Nitrate: 5.0 ppm
Ph: 7.5
High Range Ph: 7.4 (lowest range on test--probably lower)
Kh: 30
Gh: 200

This is about 2 or 3 days after a 10G change.

Tap water is about the same, only the Gh is 60

My fish would prefer softer water. I have posted this on other forums, asked pet store staff, I cannot figure out what is making my water turn hard. I am in the process of testing the decor in my tank to see if something is leaching out into the water. I don't know how long I should let my "test buckets" sit.
I would appreciate anything, I am getting so frustrated with this!

Thanks for anything!!!!

 

[OrangeCones]

In helping others figure out problems with their tanks, I see a rise in GH over time in tanks with a lot of evaporation per week, relative to the amount of water actually being removed and replaced with new water.

Every gallon of water evaporated is concentrating GH in a tank, as the minerals do not evaporate, but are left behind to make the GH value larger over time.

My suggestion would be to increase the water changes (either amount per change or more often) for awhile and see if it lowers your GH. Another possibility is to use RO water for a few changes, as it will dilute the GH since it brings in close to zero (depending on how well the RO source is).

I have a species of fish I am trying to breed and they like very soft water (mountain streams are their normal habitat). I have mix RO water and tap water to get the GH that mimics their native water. If the aquarium water has had a lot of evaporation (common in the winter where I live when the furnace runs, drying the air, which increases water evaporation), I must make water SOFTER than they need for water changes so that it balances out the overall GH after the water change.

Make sure, whatever you decide to do, to go slowly. Large changes in water parameters can be very stressful to fish.

 

[dana]

I have very little evaporation in my tank--I never have to add extra water between changes. I am also concerned in that the difference between my tap water (very soft filtered rain water Gh: 60) vs. my tank water (very hard, Gh 200) is so very different--there has to be something in there! There is also no mineral build up on the tank.

 

[OrangeCones]

Even if you do not add water between water changes, I'm sure you have some evaporation that could be contributing to the increase in GH.

How long as the water been at a GH of 200? Do your fish show any signs of illness or discomfort?

 

[James [Tormenter370]]

so what would you consider well water to be safe?

 

[dana]

Thanks,

Our main source of water here is a cistern--water is collected off the roof into a underground tank--and then heavily filtered. Most people around here use them. We test ours from time to time for bacteria./nitrates/nitrites, ect. We drink it right out of the tap. This is what I use to fill my aquarium. It is very soft, with a low Ph due to being rain water.

The water in my tank has turned hard from almost the beginning, about a year ago. My fish have never been very hardy, and I have had too many deaths.

I put a really big piece of driftwood (purchased for aquariums) in the tank, it seems to help soften the water a bit, but now my poor fishies are really stressed out.