Hi All,
After posting my latest system http://backyardaquaponics.com/forum/viewtopic.php?f=18&t=6090 a question arose regarding the effect diatomite may have on my FT water PH. So I did a very quick test on Saturday to see if I couldn't get some leaching into water and then test that waters PH.
In issue 3 of BYAP magazine diatomite is road tested with other mediums to see if any one medium proved better for growth rates than another, the description stated that it had a low PH of 5.5.
My TDS meter is probably not reading very true, I use it in part of a process to make colloidal silver and it hasn't been calibrated since purchase.
As for the PH readings I offer an explanation at the end.
Here's my method for the experiment and it is probably flawed.
Test Moores Ultrapure Water for TDS/PPM to ensure purity. This water was used throughout the test and a fresh sample was used as a control for every test.
Fill 1 cup with ½ cup diatomite and fill to brim with water. Agitate gently. Allow to stand for 20 minutes.
Fill 1 cup with ½ cup crushed diatomite and fill to brim with water. Agitate gently. Allow to stand for 20 minutes. Then test samples.
(what's interesting here is that the un-crushed diatomite reacted immediately on having water poured onto it, it fizzed like a carbonated drink for about a minute)
Test EC/PPM of sample water, along with crushed and uncrushed diatomite water.
All test tubes were washed rinsed and shaken twice using the pure water for every test.
Tests include PH, High PH, Hardness and Copper contamination.
In every test photo I've shown, water (PW), whole diatomite (WD) then crushed diatomite (CD) samples.
Results are as follows.
PH =
PW: 6.2 approx
WD: 6.0 approx
CD: Inconclusive/unreadable
High PH =
PW: Not on scale?
WD: Not on scale?
CD: Inconclusive/unreadable
General Hardness =
PW: from 0 to < 17.9ppm GH
WD: < 35.8ppm GH
CD: Inconclusive/unreadable
Carbonate Hardness =
PW: 0° to < 1° DKH
WD: < 2° DKH
CD: Inconclusive/unreadable
Copper contamination =
PW: 0
WD: 0
CD: Inconclusive/unreadable
So there you have it friends, in conclusion my results are a little ambiguous and mostly inconclusive. The poor outcome is basically the result of not having accurate equipment.
Discolouration of sample water is always going to make using litmus paper or indicator fluid a clumsy and inaccurate affair. This is a problem we come across fairly often at the shop. Hydroponic nutrients especially two part A&B mixes, are commonly dyed different colours to one another, like red and purple. So as you can imagine trying to sample PH is going to be nigh on impossible using the hobbyist methods above.
I think I'll invest in a multi purpose electronic PH and PPM meter as soon as possible. They're easy to use, really accurate (as long as you keep them calibrated) and they give a true result instantly on an LCD display.
Cheers,
Kri.
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