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Effects of very high KH

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#1 samlucido

  • NANFA Guest
  • minneapolis

Posted 10 December 2017 - 06:49 PM

My 65 gal tank has 2 brown bullhead and 2 sunnies. The sunnies are either Ozark Missouri Longear or North Longhear or Western Dollar. I started with some of each and have thinned the tank to 2 but not sure which I have left. But I don't think the species of sunfish is relevant to my question.


I've had my tank for about a year and have always replenished water changes (10% to 30%) with about 50% RO and 50% City water. The City water is reported to have 390 ppm hardness (per the City). My API test of the City water found greater than 200 ppm KH and greater than 360 ppm GH. 


The blending of RO and City water has kept the tank water KH and GH between 100 and 150 ppm. pH is generally around 8. For simplicity, I'd like to start using straight City water. I assume this will drive the KH/GH much higher. Would KH/GH in the range of 200 and 360 ppm respectively be a problem for these fish? should I continue with the 50% RO and 50% City water?                                                                                                             

#2 gerald

  • Global Moderator
  • Wake Forest, North Carolina

Posted 12 December 2017 - 09:45 AM

I'm guessing the GH and KH in your tap water are pretty close to the concentrations in the lake or river that the raw water is drawn from.  With hard raw water, I doubt the WTP operators would have any reason to add stuff to make it harder.  For fish and invert species native to your area, it shouldn't cause any problems (other than annoying lime-scale for you to scrape off).

Gerald Pottern
Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel

#3 az9

  • NANFA Guest

Posted 30 December 2017 - 11:36 AM

I have titanium steel aquarium heaters I need to soak in vinegar to help remove scaling. (Use an Amway scrub bud to scrape off) My water that is about 500 mg/l hardness. 


I fill a 1 inch diameter (or is it 3/4 inch?) piece of PVC with a cap on the end with vinegar. Put the heater in it (unplugged in of course). 

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