Rainwater issues

[Wendy]

Several years ago we moved to a rural property and I am now in the process of setting up new fish tanks. We do not have access to scheme water and use rainwater stored in large tanks around the property. This water sometimes sits in the tank for up to 12months. We do not add chlorine etc to the tanks.

Under the sink is an Everpure water filter for drinking purposes in case anything nasty ends up in the tank. I also use this for filling the fish tanks. It is supposed to remove the following: Dirt, rust, turbidity, bad taste, Chlorine, Chloramines, mould, asbestos fibres, oxidised iron, oxidised manganese, oxidised sulphides, limescale and microbiological growth. It has a micron rating of 5.

Water parameters as they come out of the filter are in the following range.
PH 7 to 7.4
KH >1 to 2
GH 2 - 3
Amonia 0 - 1.0 ppm
Nitrite 0
Nitrate 0 - >5 ppm

The variance seems to happen when we have a large amount of rainfall. (dilutes PH KH GH Ammonia and Nitrate) Rain sometimes doesn't fall here for 9 months of the year, but the first tests I did this year were prior the winter rains and this is where the higher numbers are represented.

I would like to get some Discus in the future and am concerned about the ammonia that builds in the water over summer. I think I will have to find a way to remove the ammonia before doing water changes and am hoping you can advise me on the best way to do this. Also would love your advise on any minerals etc I should be adding.

Currently I am just adding Cichlid Lake Salts to my 350L Rainbowfish tank and raising the GH to 5 - 6. I also add a bit of carbonate hardness generator if the KH drops to >1. They seem to be coping with the low ammonia levels better than I am...(going grey worrying about it!) But I know this is less than ideal and would like to do it better.

[BigDaddyAdo]

You can store the rainwater in a holding tank or tub and run a mature filter on it to remove the ammonia. Hopefully it won't raise the Nitrate reading by too much.

The Ph is extremely high for rainwater. How much does this vary before and after rainfall?

[Wendy]

The lowest I have seen it (after about 30mm fell) was 7.0 Highest was prior the rain at 7.4.

[Old Dave]

Wendy, is it a concrete tank?
Next time it rains, test the rainwater before it goes into the tank and compare it to the current readings.

hth,

Old Dave

[Wendy]

We have rain forcast for this afternoon, current measurements are
PH 7.2
KH 2
GH 3
ammonia >0.25
nitrite 0
nitrate >5

I will be sure to do some more sampling once the rains finishes, this is supposed to be a big front. Unfortunately for the last 12 months my area has been just missing a lot of it. Seems to rain just south of us and also just north of us, so all fingers are crossed at the moment...makes typing very hard...lol

Our rainwater tanks are all either steel with plastic liners or poly tanks. I have shell grit in the leaf catcher tray at the top of each tank that incoming water goes through before hitting the tank. Figured it would help the KH. I think its working because prior to putting it in there the KH was always <1. GH of 3 is probably due to the initial startup of 2 new tanks with around 12 inches(depth) of bore water. We have to do this when installing new tanks to hold them stable until we get some rain. About 11000 g was recently transfered into the main tanks from these new tanks and a small portion of that water would have been bore water. It's the only explanation I can figure. I do know after the last lot of rain we got which was a reasonably good fall (around 30mm) the PH dropped from 7.4 to neutral.

[Exotic Aquatic]

Wendy, is it a concrete tank?
Next time it rains, test the rainwater before it goes into the tank and compare it to the current readings.

hth,

Old Dave

+1! try and collect some in clean washed plastic if you can, just enough to test.

[Wendy]

Ah.....good idea, will put my fish bucket out now!

[ILLUSN]

The shell grit is bumping up your ph and kh. Take some water out of the tank and let it aerate for 24hrs in a bucket. This should let your tempoary hardness bubble off and likely degrade your ammonia. If you could test the water after 24 hrs in an aerated bucket and post the results we might be able to stop those gray hairs.

[Wendy]

Yay last night we had 25mm of rain.

Whats coming out of the tap now is:
ph 7.2
kh 2
gh 2
ammonia <0.25
nitrite 0
nitrate <5

The water collected in the bucket was:
ph 6.4
kh <1
gh <1
amonia 0
nitrite 0
nitrate 0

I will do the 24 hr aerated bucket test today.
Thanks everyone for your help here.

[Wendy]

ok results below for tap water aerated in a bucket.

direct from tap: 25/6/11
PH 7.2
KH 2
GH 2
Amonia <0.25
Nitrite 0
Nitrate..slight trace

24 hrs later after being aerated with an airstone
PH 7.4
every thing else the same.

waited another 24hrs still aerating
no changes.

Why would the PH go up? weird?

[ILLUSN]

Can't explain that you would expect the temp hardness to bring the ph down not up.

[Old Dave]

I have shell grit in the leaf catcher tray at the top of each tank that incoming water goes through before hitting the tank.
Figured it would help the KH.
I think its working because prior to putting it in there the KH was always <1.

I suspect your shell grit is "helping the KH" but is it in the direction you want?
With Africans you might want to increase the hardness but, as you know, Discus prefer softer water with a lower pH.

Can you keep one tank for softer water? Better for washing & drinking etc.
Your shell grit will probably be accumulating in the base of the tanks.

To resolve the ammonia issue you might check up on how some people use Matrix.

jmo, hth to keep the discussion going.

Old Dave

[Wendy]

I thought the shell grit would increase the Kh slightly and also affect the PH. But I thought GH was a separate issue. Please feel free to tell me if I'm wrong.
I had a problem with the ph dropping in my rainbow fish tank about 6wks ago and thats when I put the shell grit in the rainwater tanks to buffer the ph a bit.
I was going to keep the Discus in the same water with the KH at 2 but not increase the Gh like I do with the rainbow tank.(Iv'e been using cichlid lake salt, but changed this week to Seachem Replenish coz my plants didn't like it)

Is KH2 and GH 2-3 and a fairly neutral ph OK for growing up a group of smallish Discus?

I can remove the shell grit from 2 smallish rainwater tanks by the shed where I intend to set up a fish room eventually, that way if I ever get to breed some of them I would have some ready made soft water right by the fish room.

Or I can take all the shell grit out of all the water tanks and just put a small bag of it in the cannister filter on the rainbow fish tank....would that be a better way to go?