Re: How effective is mangrove-filter
#7
I had a 'Walstad' tank at one point, it was a 350 litre 4 foot one that I had two small fancies in. I did quite a lot of research into it at the time, but would have to revisit it a little now! It worked really well, nitrate and phosphate both consistently lower than the tap water, and no sign of ammonia or nitrite. I did do water changes on it, whereas Walstad reckons you can get away without doing anywhere near as regular as we're used to. I just did enough to hoover up any grot lying on the surface as one of the fancies was a veiltail so I had to be careful with keeping the gravel surface clean for him to sleep on at night, as he liked to do. I added a filter when I had to move some other fish in there, and then they made short work of most of the plants anyway!
I stripped it down completely in the end but I suspect I may have misread what I thought was a problem. I kept getting bubbles coming from certain areas of the substrate which I assumed where anaerobic patches. Some of the fish had a few health issues at the time which I thought were linked to the substrate 'going bad', but when I moved the fish to another tank and stripped it down there wasn't the tell tale smell I was expecting. The soil hadn't really taken to life under water but it wasn't that horrible eggy smell. In hindsight I suspect I didn't have enough flow going round which is why the fish weren't 100%, and I think the bubbles were nitrogen gas coming from the bacterial activity in the substrate.
This is it before I put the fish in, I left it a few weeks for the plants to establish (they did get quite a bit bigger than this too!) :
In a long winded way, I'm getting round to the point that plants can do a lot of good if you get the balance right, and mangroves are one of the ones which seem to get a good result as water purifiers so it's possible that Nathan's lack of ammonia etc. is at least partly to do with the mangroves
I'd be very interested in seeing any attempts at a more detailed set up though, the plans for the bigger tank sound good
It's Not Just A Fish