Water parameters for geos and uaru, high pH but low gH/kH?

[David R]

I just tested my 1400L with the cement background after 10 days with no water change, pH is 7.5, gH is 40 and kH is 30, which is pretty consistent with what it has been for the past few months even with more frequent water changes. I've never completely understood the relationship between these parameters (hated chemistry at school, was far more interested in biology!), but am I right in thinking the gH/kH are far more important than the pH?

I know keeping geophagus and uaru in hard water can lead to long-term problems, but what about water that is fairly soft but basic (not acidic)?
I'm planning on setting up a rain water tank to supply the fishroom with water, so hopefully that should help bring the pH down. My tap water has a pH ov >8.0 but very low gH and kH. There's plenty of wood in the tank, and I might add a bit more now that I don't have to worry about leaving swimming space for an arowana.

Cheers

 

[edburress]

am I right in thinking the gH/kH are far more important than the pH?

Yes, much more IMO

I don't think you'd ever have a problem with Geophagus in neutral pH. I am confused though, you said your tap water has very low gH and kH but that your 1400L tested at gH 40 and kH 30... that's liquid rock compared to "very soft" water.

I don't measure gH and kH, but I measure TDS and have always had success with Geophagus and other eartheaters in TDS 30-150, which converts to 1-6 gH.

 

[ryansmith83]

I've been wondering about this myself. My city claims to have "soft" water but the TDS is about 100ppm here. I've never measured the gH/kH. My pH is pretty high though, probably around 7.6 - 7.8. A lot of my South American fish thrive in it. I'm not seeing HITH in my Geos and my wild notatus spawn like crazy here. I also have adult Heros 'Atabapo', Krobia, etc. and they all look and act perfectly healthy, good colors, etc. So maybe the hardness is more important than the pH for those fish?

 

[David R]

I am confused though, you said your tap water has very low gH and kH but that your 1400L tested at gH 40 and kH 30... that's liquid rock compared to "very soft" water.

I should have said those numbers were ppm, according to the conversion on the test kit I'm using gH of 40ppm = 2.24dGH and kH of 30ppm = 1.68dGH. Those numbers seem more comparible to yours, but I'll try get a test kit for TDS. I'll also measure the tap water again tomorrow to see what it comes out at.

According to the test kit kH of 20-80ppm is "normally associated with a low pH (good for fish that prefer acidic conditions)". And according to wiki 0-60ppm = soft, 61-120 = moderately hard, 121-180 = hard and >181 = very hard.

 

[Cookie*]

I have been curious how this all effects a black water fish long term; having a uaru or geo for example, in harder water (with a stable neutral ph) long term? Are they more likely to develop health issues or die younger than in softer water with the same ph?

 

[Mr Pleco]

Stable environment is the key to long term care..

Couple of your statements I'm not following.. anyway... most people on this forum will claim their PH is 7.8 thats because thats the highest the test kit goes.. make sure you have a high ph kit to get an accurate reading...

KH is the most important as to keeping your ph stable., nitrates, driftwood and co2 in an established tank work to lower KH which in turn starts reducing PH.

consistent, frequent water changes goes a long way in keeping your environment stable.

My tap is liquid rock however it has low KH value, so if I let is sit for 24 hours before adding to tank, the ph values plummet.. from 9.0 down to 7.2....I use seachem reef builder in my repalcement water to keep my KH levels stable.
My discus tanks are stable at 6.5 PH , my central and african cichlid tanks are stable at 8.2 PH


for softwater fish it has been mentioned get a TDS meter and work to keep those low..TDS meters can be used however unless your breeding fish I find it's not necessary

 

[David R]

Stable environment is the key to long term care..

Yeah I'm aware of that, which is why I'm not going to go adding buckets of pH down and other chemicals to try alter it. But its only true to a point, if you're keeping soft water fish, especially more delicate ones like S. daemon or Uaru f., then regardles of how stable it is you're going to have problems long-term if the water is too hard.

I currently have a stocking of peat sitting in the sump, but I might add more and put it in a spare canister filter to try get a bit more flow going over it, and I'll add some more driftwood too. I'll look into getting a TDS test as well.

 

[ar0wan]

..nitrates, driftwood and co2 in an established tank work to lower KH which in turn starts reducing PH...

wat?

..My tap is liquid rock however it has low KH value

watwat?

..for softwater fish it has been mentioned get a TDS meter and work to keep those low..TDS meters can be used however unless your breeding fish I find it's not necessary

you hint at the diff between TDS and CO2
but WOW