Replacing ro/di filters etc

lastlight · #1 01-30-2007, 06:57 AM

Hi,

I have been running my aquasafe 100 gpd unit for about a year and never got around to changing any filters or resin. I read that the filters need to be replaced every six months or else the membrane itself willbe destroyed.

I'm battling some crazy algae now and I'm thinking it's my water. I intend to get a tds meter soon but for now I'd like to know whether i need to replace all filters AND membrane?

The tank is about 75 gallons and i change about 10 gallons every 2 weeks an topoff a gallon or two a day as well.

Thanks guys

Brett

christyf5 · #2 01-30-2007, 02:11 PM

I would just change the filters and DI. Likely they're clogged up with all sorts of stuff by now. I usually change the filters every 6 months or so along with the DI if I have it. I've just changed out my 3 year old RO filter and it was still working fine when I changed it, I just thought 3 years was probably getting close to its life span.

mark · #3 01-30-2007, 03:34 PM

I just did mine a little while ago after being in service for a year plus. My TDS normally was in the low single digits but hadn't tested for quite a while. Getting a little bit of cyano so started testing and found my TDS had crept up to 20.

Was something how dirt and heavy the filters were and though the resin still showed a greeny clear from the outside, when dumped it out, the inside had pretty much had all changed to red/black.

Psyire · #4 01-30-2007, 07:42 PM

There is no 'set time' to change filters. Basically everyone's time is different and generally a direct result of how high in TDS the source water is. The higher the TDS in the source water, the more often you'll need to change filters. You definately need a TDS meter to figure this one out..

Jaws · #5 01-30-2007, 08:30 PM

I'm in the same boat as lastlight with how long I've had my filters in for and I use the exact same RO unit. Can anyone tell me what I should replace after this amount of time and approximately what it's going to cost?

mark · #6 01-30-2007, 09:34 PM

Probably the best indicator is TDS and consider rejection rates for the membrane and Aquasafe's recommendations (900g life (or every 6 months based 150g/month)). Vague answer I know, but again in my case, had single digit TDS forever, then I get 20. Been using a year, evaporating 1-2 gallon/day plus water changes, a year seems reasonable at least for me.

Aquasafe filter changes in their instructions towards bottom.

Aquasafe's site has prices. Problem is they don't sell individual changes and recharges but years worth. I was lucky in Edm was able to split an order.

christyf5 · #7 01-30-2007, 09:54 PM

It also depends on how often you use your RODI. I only used mine for probably about 10gallons per week with a 15 gal water change every 2-4 weeks for the first couple of years that I had mine. This past year or so I've upped it to about 20 gallons a week as I've been doing weekly waterchanges without a sandbed.

Personally I'd just replace them every 6-9 months or so, even though the water is pretty clear here and the TDS is low, those 5 and 1 micron filters can get pretty clogged. As well as the chlorine in the summer that might make it past the carbon filter if its run down and ruin your RO filter.

I also managed to get in on a group buy of filters. Buying them this way saves a ton of money (esp on shipping where Aquasafe really gets ya). I got 6 changes of filters and 4 changes of DI resin for just over $100 which makes it about $17 per filter change (with the DI ones more sporadic as theres only 4 changes of that). I priced out the filters from various stores and calculated that it would cost me about $30 for the sediment and carbon filters per change. The DI filter was about $35 on its own (not the refillable resin type though). Although you might be able to get these cheaper at a hardware store or water purification store.

Pescador · #8 01-30-2007, 10:57 PM

Here's an inline dual probe TDS meter you can monitor the water out of your R/O and DI. It came with JG fittings and probe holders.

kwirky · #9 01-31-2007, 05:01 AM

I tapped into my RO/DI so I can get either RO/DI water, or just RO water. I did it mainly to get RO water for drinking, but it gives the added advantage of keeping an eye on the TDS for both the membrane, and the DI cartridge. Don't have to use a fancy inline TDS meter this way. Do you have a backflush on there, too? That's supposed to increase your membrane's life. Here in calgary the water's hard, so I backflush every week. Also I guess you're "supposed" to backflush it if it's been sitting for a long while since it's last use.

I changed my carbon filter and the sediment filter at aproximately 6 months. Our usage is about 30 gallons of RO and about 100 gallons of RO/DI each month (if you were to average in monthly water changes of 30g). Lots of evaporation because I run a fan 100cfm for temperature control lol. Those T5's heat the liverock REAL fast