You saying my tank's not pretty?

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Not sure what you mean by "clean". The filter itself doesn't need any maintenance, I'm sure there'll be a mulm build-up under the filter plate and eventually that's going to have to be cleared but I have one tank that's been going for 2 years with no maintenance at all other than scraping algae off the glass and changing water. I don't even gravel-vac it, the water is perfect and the fish in there are top notch. As long as there is a flow coming out of the uplift pipe you know it's filtering!
The size of the gravel is important, if it's too fine it can be clogged by mulm so there's no water flow. I reckon the gravel in this tank is just right, irregular shaped and average 10mm or so. Also if the gravel is too small the fish can move it. My shelldwellers have removed 50% of the gravel/oyster shell mix in their filter and used it to landscape their tank. Also got a problem in another tank where the kribs have excavated under bogwood to create a cave and have spat all the sand into the UGF compartment. Going to have to sort that out sometime, but can't now as the kribs are looking after fry and I don't want to disturb them.
Do you see the pipe at the left hand end? That's where the tank is drilled to provide an overflow, the top of that pipe defines the max water depth in the tank. To change water I just pump water straight out of the pond filter outflow into the tank and the excess water drains out through the pipe to be dumped in the garden (until I get my recycling system sorted out properly), this skims any crud off the surface at the same time. I've only got 2 tanks, the smallest ones, that haven't been drilled (yet).
Don't know if I answered you question there James haha
Garden shed full of tanks (tropicals) and a pond.
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