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Cryptocoryne Parva Carpet

Hi all,
Akwaskape said:
Can this be paralleled to using a tds meter which I do?
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Yes. TDS meters actually measure conductivity (in microSiemens) and then use a conversion factor (usually 0.64) to give an approximation of ppm TDS.

So 100microS ~ 64ppm TDS.

You can only measure "Total Dissolved Solids" by evaporating a known volume of water to dryness and weighing the residue. You usually do this using a filter paper in the bottom of the beaker, but you need to keep the filter paper in a desiccator until the last moment (before you weigh it), or the weight tends to go down during the experiment, rather than up.

cheers Darrel
 
Hi all,
Akwaskape said:
Very interesting read on the duckweed index
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I'm pleased you enjoyed it.

I started thinking about it when the technician who worked in the water quality lab. and looked after the "bioindicators" etc. retired, and I started to maintain the lab. As things worked out the work wound down and we never got a replacement staff member, which freed up the tanks etc for other usages.

I knew that the filtration systems we had (mainly planted trickle filters) could deal with huge bioloads, so from there it was a small jump to the realisation that the same approach could produce very clean water from a less polluted water source.

cheers Darrel
 
Hi all,
Akwaskape said:
I aim to hold my dirted tanks around 5-10ppm nitrates
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My suspicion would be that most planted low tech. tanks have that sort of range of NO3 values.

The problem is that it is really difficult to get accurate nitrate levels without proper analytical kit. We use "Ion Selective Electrodes" for most quick testing etc. The probes have a limited life and cost £300 and the meter itself (which can also measure other ions and pH, with different electrodes) is ~£1000. You also need nitrate standards etc. Even with this sort of kit you are only getting a ball-park figure, and in some situations not even that.
Akwaskape said:
and around 450 tds.
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Conductivity is a really straight forward measurement, you really can just dip the meter in (without any calibration etc) and get a reliable and accurate measurement. If you have very hard water nearly all of that conductivity will be calcium (Ca++) and bicarbonate (HCO3-) ions.

cheers Darrel
 
IMG_20150515_203455_zpsicwdkvvf.jpg

Update
another trim. Removed some of the plants, that had spread either by seed or by runner, from carpet. You can now see its intended width. I've also added a crypt albida back left hoping it will have enough height to creep over the rocks. And finally the Apono Crispus sent out a new leaf. The first in 6 months or so. I think this was due to me shifting the left two rocks slightly forward and this has allowed for some direct light to hit the lower parts of the plant. You can just make it out top left ish. Now if I can only get a dozen more.

Hope you enjoy it
 
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