Subject: Re: Yellow water hyacinths and green water From: rodfarlee@aol.com (Rod Farlee) Newsgroups: rec.ponds Date: Sat, Jun 23, 2001 10:03 PM Message-ID: <20010623220325.15539.00000350@nso-cj.aol.com> Hal writes: I added 3 ounces of muriatic to the 1500 gallon pond and the next day found a new test kit, the dropper kind. My tests read ammonia and nitrites 0 and 53.7 ppm for both KH and GH and the pH reads 8.2. Are those good numbers for KH and GH, or what should they be? The USDA publication you mentioned http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/464fs.pdf recommends KH 75 to 200 ppm, GH 100 to 250 ppm. KH 3 degrees (53.7 ppm) is probably too low to keep the pH stable. I find that 80 to 90 ppm is necessary in my pond. I wouldn't add any more acid! In fact, I'd do the opposite. I'd increase KH by 2 degrees by adding 1 pound baking soda to 1500 gallons. This won't change your pH 8.2, but will stabilize it there. GH 3 degrees is also softer than recommended. It's not essential to increase it, but if you wish to do so, add about 1 pound of gypsum (calcium sulfate). (Limestone won't dissolve at this pH, but gypsum will.) For small ponds, a convenient source of gypsum is plaster of Paris; just pour it into a plastic container, let it cure, pop it out and place it into your filter or stream. It'll take about a month to dissolve, and will slowly raise GH as it does. How do you convert mg/L to ppm? 1 mg/l =~ 1 mg/kg == 1 ppm (within a fraction of a percent accuracy). 1 degree == 10 mg/l CaO = 17.8 mg/l CaCO3. - Rod ---------------------------------------------------------------------- Subject: Re: Is PH Down, PH Down? From: rodfarlee@aol.com (Rod Farlee) Newsgroups: rec.ponds Date: Sat, Jun 23, 2001 10:03 PM Message-ID: 20010623220332.15539.00000355@nso-cj.aol.com "Mark Baughman" <baughman@neo.rr.com> writes: I've been reading a few of the posts about PH down. What can be used to lower it. What I was wondering is if the PH down used for a Pool or Spa could be used in a pond. I supposed that there is a possibility that the pool PH down is more concentrated, but that would mean I just need to use it carefully. Mine seems a little high... If your pH isn't above 9, it doesn't need to be lowered. For a good general introduction, suggest the 4-page USDA publication "Interactions of pH, Carbon Dioxide, Alkalinity and Hardness in Fish Ponds" http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/464fs.pdf If your pH is above 9, then yes, either swimming pool "pH Down" (sodium bisulfate, dry powder) or muriatic acid can be used. (Muriatic acid is preferable, as it's chloride is beneficial to fish. Two ounces per 1000 gallons lowers KH by 1 degree.) Note that any acid directly lowers KH (also called alkalinity, pH buffering capacity, or acid neutralizing capacity), and only indirectly lowers pH. If KH is lowered too far, pH will become unstable. Generally, there's no need or benefit to lowering KH below 150 ppm (9 degrees), or pH below 8. Lowering KH below 100 ppm (6 degrees) can leave the pH unstable in a pond that receives direct sunlight and has algae or plants. So it can be dangerous to add acid to a pond, without monitoring KH. KH test kits are available, similar to pH tests. - Rod