continuous water change design

[Fishfanatic]

hello everyone. i have a rather technical question that i am mulling over and can't seem to solve. i have been thinking day and night but my physics-challenged mind has not been able to grip the problem.

Here's the hypothetical problem:
suppose i want to add a continuous supply of ro water (suitably reconstituted) to my tank. My tank has a sump with a few baffles (ie. dividers) in it. the tank itself has an internal trickle filter/overflow with the usual comb.

I figured that i would need a drain pipe to drain the excess water from the system that is displaced by the added ro water.

the QUESTION is: where do i position this drain pipe? at the sump between one of the baffles or at the top of the tank? if in the sump, between which baffle would this drain pipe be best located? if in the tank, where will the pipe be positioned, height-wise in relation to the overflow comb height?

if anyone cld help...solve this prblm... wld be grateful..cheers.

[CK Yeo]

I'm not an engineer, but I dun think it will matter considering the flow rate/ turn over of sump systems anyway; I would think that the turnover is usually high enough to consider all the water as homogenous. So IMHO, I dun think it matters where you put it, as long as it is asthetically pleasing. I would have positioned it in the sump.

but if you want to get very technical, there'll be minute differences between the water quality before and after the sump due to whatever biological/chemical filtration you have. Then you will probably want to put it anywhere before it goes into the sump.
Also, depending on the flowrate of your RO, it might not have any difference (or negligible difference) where you place it.
I doubt you will be able to see the difference with the hobbysit test kits anyway.

Height wise will be obvious. Position it where you want your water level to be.

ck

[tawauboy]

you can place the drain pipe at the first baffle where the water is coming from the tank. this is where the "dirty" water first comes in.

[Fishfanatic]

thanks for all your posts mates. was wondering abt the height of the baffles... suppose i had three. how high shld they be in relation to one another. ie not in terms of absolute measurements, but shld the second be shorter than the first, the third shorter than the second, progressively in the direction of the bottom of the trickle filter to the end of the sump that is connected to the sump pump for delivery up to the tank?

what purporse will the baffles serve in the first place?

cheers,

[tawauboy]

the baffles are meant to direct the water flow through the sump tank. the middle baffle should start from sump tank bottom to maybe 2/3 height. the 2 side baffles could have same height (higher than middle baffle) and have a large gap between baffle and sump tank bottom. this arrangement will "force" the water to flow through each baffle, which is usually filled with filter material.