Reef Discussion

[Sam Parker]

Have a read of http://reefkeeping.com/issues/2005-10/rhf/

From memory a continuous change is about 10% less effective than "big" changes (but has benefits around stability, etc).

For what it's worth I do 13L/day on a 8x2x2

Yeah I know that article came up with that figure, but it's not so easy to quantify across different tanks/sizes/amount of change/pickup points/flow etc.I always like to suggest this scenario when explaining to the "doubters". Using your example of 13l a day in a 8x2x2. That's about 86ml a time. So, imagine pouring 86ml of cordial into your tank in the return pump section of your sump. Wait five minutes, then take 86ml of water out of the chamber before the return pump. I doubt you'd be lucky enough to get 1% cordial, I reckon it would be more like 0.0000001% remembering that this is 86ml into a 900l tank at sections of the sump that require the fluid to go all the way through the tank and to that chamber again.

Conversely, do a 50% change once a month. I guarantee that you will remove 50% of the "new" water you added last month ;)

9 or 90 per day?

you can go up to 90l a day (depending on how efficiently the pump is running) and you are still only doing 600ml at a time :)

 

[macca_75]

I would like to think in 5 mins any new water would be mixed evenly across the tank.

But for what it's worth the benefits of no temperature swing, no parameter swings, not missing or forgetting changes, etc far outweighs the extra water required.

 

[Sam Parker]

Yeah fair enough. Ok, well 86ml into 906,000 is going to dilute out to be 0.00009492273%. Or to round down, zero percent of new water being removed with each change :P