Why won't anyone help.

I don't really understand your filter set up, but I want to say about the charcoal that IMO removing it is much than replacing it every two weeks. If charcoal is functioning as a growing surface for bacteria, go ahead and replace it with something that doesnt have to be changed out. Make sense?
The sense I get from these responses is, there is really no fix for those fish in that tank. A 10G (40 Litre) tank would be less than ideal for the bristlenose,but would be So much better than what you have now, that I second the recomendation that you get one ASAP.
If you can afford something in the 120Litre range right away great! That should make the bristlenose happy for life,spacewaise ( Mind you, I am going by what I read about bristlenose, never having raised one myself.)
ANYWAY....with this "proper filter i brought around 350lph box says upto a 100litre tank" on a 40 ltr tank I think you will be Much happier. There may still be high current, but at a more manageable level.
~ As far as turning off the filter at night... I think you have two filters running, right? I suppose you could turn off the whirlpooling one, run only the other and TEST the water quality... if one filter is sufficient, deep 6 the whirlpool one altogether. BUT As I said, I can't picture what your filters are, and anyway, you wont be keeping this too small tank long enough to mess with it, ;)
a Tank like that, Id be tempted to change 1/2 the water daily. again, if you did that, maybe you could lose thewhirlpoolfilter too...BUT, Even if you could have just the right amount of current, And avoid ammonia or nitrite poisoning, you will still have problems as long as those fish are in that tank.IMO
Lets hear what happens ok?
 
agreed echo, the neons and mollies aren't wild waste producers, so they might be a little cramped, but it's not terribly overstocked. besides everyone, he's already stated that he knows his tank is too small. he gets it. moving on.

i think the sponge idea is great. although your filter is a bit much for a 4 gallon, once you get a larger tank you can continue to use that same filter, so for now a sponge over the outlet is a great temporary fix.

and kudos on getting a bristlenose instead of a common pleco! for your tiny tank, that was the best thing you could have done. he won't get nearly as big as a common pleco. however, he is going to need a larger tank very soon, as plecos grow quite quickly.

i've found 10 gallon tanks for $12 at my local petco, so I'd suggest picking one up and getting that going. An easy step up and it will make things much more comfortable for your fish. even once you get the larger tank, a 10 gallon makes a great quarantine tank, and they're easy to store when you don't need them to be running.
 
thank you all so much for the response! i have decided to hit the trading post for a second hand tank and stand found some quite cheap 2ft and 3ft tanks and stands.

Is there anything special i should do to the tank apart from wash it and give it a good scrub with an alge scrubber?
 
Well, inspect the seals to ensure they are intact. Do a test fill outside and let it sit for a day or so to ensure it doesn't leak.
 
if it does leak can i cut out the seals and use "tank grade" silicone to re do them?
 
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