gH/kH Carbonate hardness, a question for the pro's

[steelhealr]

Hi...my 46 gallon FW tank is now cycled about 3 weeks and I regularly do water checks and changes. My pH ranges slightly acidic , 6.8. Ammonia 0, nitrite 0 and nitrate 40 or lower with water changes. I decided to buy a gH/kH kit today and tested both my tap water and tank. Tap was ph 7.2, gH 1 and kH 2. My tank was gH 3 and kH2. All my fish appear very healthy and except for one pair (swordtails), they all are listed as preferring generally soft to medium water hardness. One of my books states that a kH of 2 is satisfactory. One says it is low and could predispose to pH swings with less buffering capacity.Most books say don't mess with anything if all the fish are doing well. True? Would a higher kH be better to prevent an unexpected fall in pH, i.e, futz around with the kH? or..will the regular water changes, since the tap is more alkaline, help keep the pH in check assuming one doesn't overfeed? Thanks in advance. SH

 

[Griz]

Your KH is rather low so pH fluctuations are a definite hazzard for you. Regular and frequent water changes would defintely help keep things stable however. If you are doing that, you should be fine. Adding limestone to your tank may raise help your GH and KH a bit, coral works as well. These methods are work more slowly and predictably than chemicals. Your pH may rise as well but I don't see that as a problem for you, yours is pretty much neutral.

 

[modernhamlet]

Between water changes, nitrate builds up in the water, slowly lowering the kH and, eventually, pH. I used to have very low tapwater kH and always had to deal with pH dropping from 6.8 or so down to 6.0 and lower. It was a drag.

Plenty of water changes is the best thing you can do. Otherwise, as griz says, a small mesh bag in the filter containing crushed limestone or coral would do the trick. However, keep an eye on all the parameters so you don't raise the pH too far along with the kH.

As long as it's not sky high, gH level isn't generally relevant to most normal aquarium fish.

 

[steelhealr]

Griz and modern..thanks for the input.....I'll check out the lfs for coral/limestone. I have an AquaClear 70 (300) and there is room to add an 'insert' in the outflow . Thanks again. SH

 

[steelhealr]

PS...is there a brand name or product that you can recommend to use as an insert? Thanks. Frank

 

[Def]

There is an easier way, add a half teaspoon of bicarbonate of soda to every 10 litres of water, every time you do a water change (add it to the fresh water, stir it well, don't add it to the main tank). If you do it slowly over a period of time, you can raise your KH without affecting PH. Your KH is the same as mine, you'll need to add huge amounts of coral to the tank to raise it that way. I did it with the soda method, took a while to get from 2dkh to 10dkh but now it's stable.