Water Chemistry KH/GH

[Matt B]

Hi folks,

I have a guppy tank that I set up before I was fully aware of how fine an art water chemistry is. When I set the tank up I added a couple of handfulls of crushed coral and a couple of fist size lumps of tufa rock, now the tank is a few degrees harder (GH) than the tap water but still not quite of an optimum hardness for guppies.

If I add some more crushed coral gradually to get the gh/kh up a bit more, is it ok to then treat the tap water im using during a water change with some bicarb and epsom salts - or will this harden the tank even further?

At the moment Im battling nitrates due to a slight population explosion by performing daily water changes, however I noticed the fish are a bit unhappy directly after a change of water for a few hours - I was advised by someone on an another forum it may be due to the TDS levels being so different between tap and tank, something I was unaware of until earlier this week when I got my gh/kh test kit and TDS meter.

Cheers all

Tank water - Thursday 12th July 2012
Daily water changes at 17%

342ppm - TDS
35.8 - 40ppm (2 or 3 drops kh)
89.5 - 95ppm (5 or 6 drops gh)
PH 8.1

Tap water

PH 7.6
114ppm - TDS
35.8ppm (KH)
35.8ppm (GH)

Edit:
I was going to be setting up a second tank to split the population males and females. Im wondering now if it wouldn't be a bad idea to get the tanks around the same level and just move all the fish to the bigger (new) tank and then start from scratch without the tufa and coral with the old tank, since they have quite a variable effect on chemistry dependant on acidity

 

[fort384]

I think your plan that you added sounds like the best route. Messing with GH/KH is not necessary in most cases (and in your case the tap water is suitable for guppies).

Welcome to AA, by the way

 

[Matt B]

Hi, thanks for the reply. I was led to believe from reading other sources that my general hardness is "soft" and that a level of 9 dgh or higher is best for guppies? Working out my tap water into german degrees this makes it only around 2..
Since I live in a very soft water area (still not sure why the PH of the tap water is so high) I assume the guppies are bred in softer conditions than in the wild, so I was reasonably happy to learn that the tank is at around 5 dgh - a happy medium.

Does that sound anywhere near right?

 

[fort384]

While it may be true that a bit higher GH is optimum the consequences of attempting to change it outweigh the benefits. I think you will have success breeding in your softer water. Guppies are not too particular.

Sounds to me like you are on a good path.

 

[Matt B]

Well the little guys seem to be in their element with the tank the way it is and Im keen to not have to mess with the water too much. A couple of days ago I added around 500 grams of crushed coral to my 20L fresh water bucket, after it sitting for 48 hours with the coral it nearly matched my tank conditions perfectly. If I can get away with keeping it like that, it suits me fine. My only bug bear now is the difference between TDS of the tap and tank. It kind of limits me on the size of water change I can do without upsetting the fish. I tested the fresh, bucket/coral water for TDS and it had risen slightly but Im still unsure of whats giving me such a high reading in the tank in the first place, I can only assume its due to the length of time the tufa rock and bit of crushed coral have been in there....?

 

[fort384]

Yes, I would say the longer the water is in contact with the coral and tufa, the higher your GH will go, to a point.

So long as you can reasonably match the water for water changes, it will be fine. But I would still ditch the coral and tufa, and just use your tap water. It will simplify things big time over the long run. If you cannot get the parameters close before adding water, it could cause osmotic shock and seriously stress the fish.