Fish/food loading - you have it in one. Copied a few emails I had with Mike Snaden, he agrees with you, thought these might interest you though.
Hi Mike,
I dipped my TDS meter in my 450 gallon growing on pond during the week and was really surprised to see it at around 500 (bet that gave you a smile). I recently installed a static K1 system into the front end Vortex to take out some fines, thereafter it pumps up to some stacking boxes as a shower. 3 boxes, first with BHM, then grog, then Glafoam. This Glafoam was some trial media that was made fro shells and a think glass. It made a ‘lump’ media, full of tiny holes, so looked OK to use as a media. My initial thoughts were that somehow the shells in the Glafoam were buffering the KH up and therefore I would get a higher TDS. The tests I done today do not show this and it looks like ‘crap’ in the shower which is the problem.
Turnover is 462 gallons (on 450 capacity), loads of air, loads of food. Food I’m now using is some that Duncan had made up, which he says is full of top ingredients and minerals etc. Just as you’d expect from Dunc, top stuff. There is little waste from this food, although I’ve only been using it for the past 3-4 weeks. Previous food used produced loads of crap, some which got through to the showers, prior to the static K1 being introduced.
Hi Bob,
Can't comment on the Glafoam as I have no idea what it is. As for Grog... in the long term, it won't work, it will just block up and fester. But, given the MHB you already have in the system, I don't think it will be much of a problem.
Your pond KH is quite a lot lower than the fresh water KH, which coupled with the high TDS, means that not enough water is being changed.
The muck on the Shower will have no effect on the TDS at all. Even if you were to somehow remove any dirt on the Shower, and drop it straight into the water, although the water would look frightful, it wouldn't raise the TDS. The TDS would only rise when that dirt gets broken down by bacteria from solid organic waste, into ion (chemical) form, in which case, it is then dissolved, and WILL raise the TDS.
If you change more more water, the organic load which is contributing to the TDS will be diluted. At the same time, because of the higher quantity of fresh water going in, your KH would rise. By doing this over time, I would be happy if the TDS dropped to around 280, with the KH rising to nearer 190.
Thanks for repying Mike,
Say the drop in KH, but as there was still ‘loads’ left I didn’t see it as an issue.
So is there just too much organic load for the filter to cope with do you think? Is the filter converting the load dissolved into the water? I know the Koi and food fed ratio is high for the small amount of water. Will reducing the amount of feeding over a period of time, just lower the TDS? Or is it a water change issue? I could run some water through it to overflow, if I add an overflow!
If Grog will ‘fester’ long term, this is in the shower though. Quoting what you just replied, if it even collected solids/crap/solids in the shower, why would this not be OK, unless it was broken down into dissolved ion form. I always thought that crap in the filter was not good and would be of detriment to the water quality.
Bob,
Ooooohhh... you pose some interesting questions!!!
First, granted, your KH is fine. I would personally be happier to run a KH of around 30ppm, but to to this with your pond, I would have to not change any water at all for months, at which stage the TDS would be through the roof.
In your case, your TDS is telling you that you aren't changing enough water in relation to the loading on the pond. Your KH is reflecting this also.
Doesn't matter what the organic load on the filter is really, as at the end of the day, waste gets continually broken down, some of it into gases, and some into water soluble ions. Basically, if you have a 450 gallon pond, that is stocked and fed as if it were a 3000 gallon pond, then you need to change water as if it were a 3000 gallon pond.
As for grog collecting waste and festering... Take a piece of BHM out, and break it open, or smashed it to a pulp. Then do the same with the Grog. Compare the smell and state of what's inside. If the grog stinks like sulphur, and is blocked full of shite, bin it. It is isn't, keep it for the time being. You are right in respect of waste being trapped on the media not affecting TDS, but you don't want it creating bad bacteria either (smell).