Water very hard - do I add Ca and Mg - Fertilizing

mark77ap · 06-02-2008, 05:45 PM

Hi,

I have been doseing EI for about 1 year now. I seem to constantly be battling algae of some sort. I figured I would try this PPS-PRO. It sounds much easier and I like the idea of not having excess nutrients in the water.

With EI, I never dosed Magnesium or Calcium. My Tap water is 22 dGH and 11 dKH. Should I sill add the Ca and Mg to the formula for PPS-PRO? Will it raise my hardness. I have to pump in loads of co2 as it is

Thanks

Mark

hoppycalif · 06-02-2008, 06:24 PM

If you use a municipal water company tap water you can get a copy of their water quality report, which usually lists both the calcium and magnesium in the water - almost always a range of values that may be found. If that shows you have some magnesium, around 1/4 of the ppm of the Calcium more or less, I don't see where you need either calcium or magnesium. But, if the report shows little or no magnesium then adding it is a good idea.

mark77ap · 06-05-2008, 04:43 PM

Quote:

Originally Posted by hoppycalif

If you use a municipal water company tap water you can get a copy of their water quality report, which usually lists both the calcium and magnesium in the water - almost always a range of values that may be found. If that shows you have some magnesium, around 1/4 of the ppm of the Calcium more or less, I don't see where you need either calcium or magnesium. But, if the report shows little or no magnesium then adding it is a good idea.

Thanks. I do have a copy of the report but it only states the hardeness as 328 mg/L (23 grains). It does not sepcify Calcium or Magnesium individually.

hoppycalif · 06-05-2008, 06:51 PM

With water that hard I find it difficult to believe you could be short of magnesium. But, others (Edward?) may differ.

ray-the-pilot · 06-06-2008, 07:11 AM

Municipal water suppliers are not required to report water hardness; although many do as a curtesy to their customers.

It is impossible to know the ratio of Ca/Mg from the total hardness; however, with such hard water there is probably enough Mg.

If your not strapped for cash you can get a total/Ca/Mg hardness test kit from LaMotte. It’s like $60 with shipping.
If you can do chemistry you can modify the Red Sea salt water Ca kit to test fresh water by using a larger sample (50 – 200 ml). I could not get the Red Sea kit Mg kit to work on Fresh water.

Bert H · 06-10-2008, 07:49 AM

Do not assume a high gh indicates you have enough or the proper ratio of Ca/Mg. If the water source is from a limestone aquifer, chances are you will have tons of Ca, and little Mg. I have well water, gh12-13, from a limestone aquifer, and I add Mg to all my tanks. If I don't I get lots more stunted growth on certain stem plants.

hoppycalif · 06-10-2008, 11:57 AM

Bert, that's a good point. I grew up in Missouri, where the "limestone" is actually a mix of calcium and magnesium based rocks, so the water had both. But, I understand that Florida is largely a pure limestone state.