# How fast do you go through DI?



## twobytwo (Oct 25, 2014)

Just curious - I think I'm doing something wrong... Going through DI *FAST*. I understand it would be based on water quality going into it and how much water is being made. Most recently, I refilled a cartridge on Dec 17 - TDS was 0. I checked last night after probably making 120ish Gallons Over 2 weeks (water change and set up a couple QT's) and it was between 1 and 2. Is there anything specific I should be considering to help? All the other filters (GAC, Carbon, Sediment, Post Carbon) were all just changed in November.

Are all DI resins equal? The resin Im using is from ReefSupplies which I hadn't tried before November.


----------



## CanadaCorals.com (May 12, 2013)

Your membrane might be shot.

Take out the DI cartridge and test the TDS coming out. Compare that amount to your tap water. A good quality membrane will reject 97% so if tap water is 100TDS, you should get 3TDS after the membrane.

When the membrane is shot, it will kill the DI much faster.


----------



## twobytwo (Oct 25, 2014)

CanadaCorals.com said:


> Your membrane might be shot.
> 
> Take out the DI cartridge and test the TDS coming out. Compare that amount to your tap water. A good quality membrane will reject 97% so if tap water is 100TDS, you should get 3TDS after the membrane.
> 
> When the membrane is shot, it will kill the DI much faster.


Thanks for the Tip. I just checked... 135TDS going into my system, 004TDS coming out without the DI. So... right around the 97% rejection rate.

0TDS with the DI because I just changed it last night, as it I had around 1 or 2 TDS after 2 weeks. RO membrane is about a year old.


----------



## cica (Feb 10, 2013)

What kind of DI canister do you have? Is it in vertical or horisontal position?
The reason I ask is I have an Aquasafe system and originally the DI canisters (3 of them in series) are mounted horizontally. In this position the DI media is on the bottom, leaving a little bit of water on the top with no media. Some of the water goes thru not, or bearly touching the media. After using it for a short time this way I had the same problem. Now I have the canisters mounted vertically and no more problem, the water has to pass thru the media properly.


----------



## blunthead (Jan 24, 2011)

twobytwo said:


> Thanks for the Tip. I just checked... 135TDS going into my system, 004TDS coming out without the DI. So... right around the 97% rejection rate.
> 
> 0TDS with the DI because I just changed it last night, as it I had around 1 or 2 TDS after 2 weeks. RO membrane is about a year old.


what dan said was to check the water after membrane before it goes to the di,
the membrane if its good should bring it down to about 004 then the di should take it down to zero
if the tds is much higher after the membrane itll kill your di again in now time


----------



## Mikeylikes (Nov 22, 2013)

Something isn't right. I'm still using the same membranes/filters since I first started my tank over a year and a half ago and I still get 0 TDS. 

I do 30 gallon water change every 2 weeks so do the math. It's much more volume than what you have produced so far. Hmmm ... Ditto to what 
Dan said.


----------



## rburns24 (Jan 31, 2011)

-
Sounds like whatever you are using to measure your TDS is kaput.
-


----------



## Sunstar (Jul 29, 2008)

cica said:


> What kind of DI canister do you have? Is it in vertical or horisontal position?
> The reason I ask is I have an Aquasafe system and originally the DI canisters (3 of them in series) are mounted horizontally. In this position the DI media is on the bottom, leaving a little bit of water on the top with no media. Some of the water goes thru not, or bearly touching the media. After using it for a short time this way I had the same problem. Now I have the canisters mounted vertically and no more problem, the water has to pass thru the media properly.


How do you connect hte canisters? Because I have the aqua-safe.


----------



## cica (Feb 10, 2013)

Sunstar said:


> How do you connect hte canisters? Because I have the aqua-safe.


The connection is the same as when they were in horisontal position, just need longer hoses. I just mounted them vertically to the plywood sheet, with the rest of the system.


----------

