Originally Posted by
cooper666
I am setting up a similar filter to you - Tap water > Activated carbon >Fish tank sump > Overflow (waste)
I think good GAV is your second best option to RO regarding removal of all sorts of nasty stuff, will not help with the TDS though. 700ppm is pretty salty.
Is your tap water turbid? If not I'd scrap the sediment filter and replace it with a 5 micron carbon filter, followed by one or more 0.5 micron carbon block filters. Why dose prime after the carbon? Does it have EDTA or similar in it?
Things that I'm considering with my setup
-Continual overflow is very inefficient compared to removing a "chunk" of water and replacing it, therefore a larger quantity of water is required, this extra water will require heating, thus, water consumption + power consumption increases
-Im worried that the carbon will become spent and I'll dose my fish with chlorine accidentally. I'm looking for a constant chlorine monitor system, but apart from ORP monitors (which I hate) there isn't much available. Either way, I know that regular testing for chlorine in the incoming will be necessary or one day I will fry my fish, guaranteed. To soften the blow of accidental chlorine in the tank, I plan to put the inlet at the beginning of my biofilter (MBBR). This will help to degas the water and if any chlorine comes through it should burn itself out on the bio filter bacteria, softening the blow to the fish.
-If you push water through the filter fast, there is more chance of chlorine making its way into the tank. I've deliberately restricted the filter piping to 4mm lines, which restrict the maximum flow rate through the filters. If someone accidentally opens the valve, It won't exceed the de-chlorinating capacity the filters. (I hope)
Personally, I really like the idea of constant exchange, however, there are risks which cant be ignored. IMO the most important thing is to test, test, test, test........., you get the idea.