ro-di filter necissary?

First 0 TDS may not be 0 TDS. Spectrapure has a very good write up on this both on their website and on their forum on Reef Central.

The biggest difference in units is initial cost versus operating cost. If you consider, for every 2% you increase the RO membranes effciency (90% vs 96 or 98%), you double the life of the DI resin. That can be a significant cost savings even in one year alone. Figure the cost of several DI cartridges or even bulk refills and you now have as much invested as you would have with a better unit to begin with. Also many units today will never see 0TDS even on their best day, the components and design just will never do it. Many Chinese clones being sold look similar but fall down on performance.

 

+1 great advice there.

 

I use a 'drinking water' addition to the sink by Culligan where I change a level 4 carbon block cartridge filter every 5-6 months. Undersink Water Filter, Level 4 # US-EZ-4 by Culligan

it has a .5 micron filter.

I never have any problems with algae or high nitrates. I've a water softener in the house where I believe the unit taps off of. I always read about it being a must to use ro/di, but it's a hard sell if my tank's been running successfully w/out buying a dedicated unit just for the tank. I just use it for top off. Only issue is the very slow production of water.

ps. Bogie, i love your sig line btw...awesome.