Hot Tips: Water Purification Tips

A selection of useful tidbits of information and tricks for the
marine aquarist submitted by Advanced Aquarist’s readership. Readers
are encouraged to post them to our Hot Tips sticky in the General Reefkeeping Discussion forum or send their tips to for possible publication. Next month’s Hot Tip theme will be “Online Purchasing Tips“.

Water Purification Tips:

Add a DI to your RO unit. Even with 1-2 TDS coming out of the RO you
can still have all sorts of undesireables making it through.



Get the highest gpd unit you can afford. More gpd means more RO membrane. More membrane means longer life for the filter.


Clean your water storage containers with a water/bleach mixture.
Rinse well with freshwater and allow them to dry completely before
refilling with purified water. There isn’t much point in putting RO/DI
water with a zero TDS reading in a container that isn’t completely


Don’t get an RO membrane rated for more than 75gpd for household
use. The pore size on those membranes is too large and it lets too many
contaminants through.

Use a pressure gauge to check your sediment and carbon filters for
clogging. If the carbon isn’t working the chlorine will destroy your RO

Never add the solids in limewater to the tank, that’s where any
residual heavy metals will end up. This also means that limewater will
remove heavy metals when used properly.

Get a good TDS meter for your RO/DI water and use it!


When setting up a new and large tank (100g+?) use a household point
of use filter (Pur, Brita) to filter the water. Add your mix, live rock
(to cure) and run carbon, and a PO4 remover 24/7 untill cycled. Water
ends up as good as RO and you didn’t have to wait 8 days while your RO
filter made 320 gallons of water.

Rob Top

I use two sediment filters and a tfc membrane rated for 125gpd. Get
clear canisters so you have a visual of the sediment filters as they
age. Locate a good place to stock up on filters and do so. I usually
buy a years worth of filters at a time.


Clean you storage tanks and if you have a separate salt tank you
need to have a powerhead in the tank to stir the water. Set it up on a
timer and run it twice a day for 25mins.

Always use a shut off device.


Buy a ro/di unit that comes with a pressure gauge and tds meter.



  Advanced Aquarist

 Advanced Aquarist

  (103 articles)

Leave a Reply