Is it time for new filters? (1 Viewer)

[Kyle]

I have an aquasafe 6 stage RO/DI water filter. Yes, I know it isnt really a six stage. My TDS meter is now reading between 5 and 9. I read 0 during the first couple of months of operation. I have had it for about 7 months. Can someone tell me if it is time for replacement and if so which filters do I need to replace? Are these typically a standard size filter? Where is the best place to purchase these? Thanks.

Kyle

 

[Guest]

Your DI filter definitely needs to be replaced. It is the one you will have to replace most often, and unfortunately the most expensive as well. How long you get out of it is a function of how dirty your tap water is to begin with, and how efficient your RO membrane is. If you have a 75gpd or less membrane, your DI will last a lot longer than it does with a 100gpd unit. The only way to really know when it needs replacing is when your TDS starts creeping up - it doesn't have to be 0, but at some point you have to draw the line and replace it. Mine is up to 2ppm after 8 months of use, and for me that's about time to replace it.

The prefilters (carbon, sediment, etc.) should be replaced every year, according to the manufacturer of my unit (you probably should check with your manufacturer to make sure). These filters wearing out will have no effect on your final TDS readings at all. The main reason you need to replace your carbon prefilters is because carbon removes chlorine from the water, which is very harmful to the RO membrane. Going too long without replacing the carbon will wear out the RO membrane faster. If you have sediment prefilters, they can reduce your throughput as they get clogged up, so replacing them may increase the production you see from the system.

The only other thing to worry about is the RO membrane itself. I believe they are supposed to last 3-5 years under normal conditions. I think some manufacturers also recommend backflushing the membrane every so often to remove any sediment that may be clogging it.

 

[Kyle]

Thanks Mike. YOu got any tips on where to get the replacements.

 

[KarenHorn]

Check out Buckeye on the sponsor's page. The prices are very reasonable and the service is great from what I've heard. It won't be long until we'll be ordering from them ourselves.

 

[AggieBrandon]

Kyle,

The water in College Station is at about 575 TDS or so (well it was when I tested it). I just ordered replacement cartridges from www.buckeyefieldsupply.com . I got a sediment cartridge, a carbon cartridge, and the di resin cartridge for about 30 bucks. Not too bad compared to other places I have seen them listed. I think Aqua-nut was selling the complete cartridge replacements for that unit for 40 bucks or so you may want to check with him. Oh and I'm not sure how often to replace the carbon cartridge but after all that crappy water in college station going through it you may want to replace it too.


Brandon

 

[Kyle]

Thanks a lot brandon

 

[Buckeye Hydro]

If you have a 75gpd or less membrane, your DI will last a lot longer than it does with a 100gpd unit. The only way to really know when it needs replacing is when your TDS starts creeping up - it doesn't have to be 0, but at some point you have to draw the line and replace it.

Well, sort of. The rejection rate on some 100 gpd membranes is 90%. Some others are 95% to 98%. Depends upon the manufacturer.

The prefilters (carbon, sediment, etc.) should be replaced every year, according to the manufacturer of my unit (you probably should check with your manufacturer to make sure)

.

Mike - let me guess - you bought your unit from ebay? The general rule of thumb regarding life span of the sediment and carbon block is 6 months. The claims being made by some ebay retailers is curious, because they don't claim to be using any sort of space-age cartridges that would double their expected life. There is an ebay retailer that routinely claims a 100 gpd Filmtec membrane will produce 110 gpd too... Buyer beware.

The life span on these cartridges is best determined with a pencil and paper, and a pressure gauge. When these filters plug you'll note a decrease in the pressure reaching the RO membrane (this is why it is nice to have a pressure gauge on your system). When you buy a carbon block, ask what the pore size is (it should be smaller than that of the sediment cart), and ask what the chlorine capacity is. Our best selling carbon block has a chlorine capacity of 20,000 gallons. Most units sold out there come with carbon blocks with a capacity less than or equal to 6,000 gallons. You want to make sure to replace your carbon block before you reach the chlorine capacity. Exposre to chlorine will ruin a thin film composite membrane.

The only other thing to worry about is the RO membrane itself. I believe they are supposed to last 3-5 years under normal conditions. I think some manufacturers also recommend backflushing the membrane every so often to remove any sediment that may be clogging it.

Flushing the membrane is a good maintenance practice. Note - there is no "back" about the flushing. When you flush the membrane housing all you do is open a valve that allows water to bypass the flow restrictor. Water rushes through the RO membrane housing in its normal direction.

As to where to buy replacements... Well, I think you can guess at my answer to that one!

Hope this helps,
Russ

 

[Kyle]

Thanks for all the info russ.

 

[dobber99]

I purchased an R/O unit from e-bay (the 110 gallon you were refering to), and my baseline TDS reading is 6ppm. I am still using the housing from my old R/O unit for extra pre-filtration (2 sediment+2 carbon) + (1 sediment + 2 carbons + 1 carbon block post R/O on the new system) I know its overkill, and may actually decrease the membranes perfomance by having less overall pressure going to it. Where on the R/O unit should you place the pressure guage. Also, Lowes sells a pressure guage, but the fitting is made of brass. Should this matter? I called Aquasafe (where I purchased my R/O unit) and they guarantee their unit to bring the PPM to < 10ppm, which it does. My water here in Kingwood is 187ppm before any filtration according to my TDS meter. Some of the posts have a baseline of 0-2. Are you guys getting your reading w/ or w/out a DI cartridge. At what ppm is considered unsafe for the reef environment, or drinking for matter?

 

[Buckeye Hydro]

I purchased an R/O unit from e-bay (the 110 gallon you were refering to), and my baseline TDS reading is 6ppm. I am still using the housing from my old R/O unit for extra pre-filtration (2 sediment+2 carbon) + (1 sediment + 2 carbons + 1 carbon block post R/O on the new system) I know its overkill, and may actually decrease the membranes perfomance by having less overall pressure going to it.

At a minimum, ditch the post RO carbon. Unless of course your fish have been complaining about the water's taste.

Where on the R/O unit should you place the pressure guage.

the pressure gauge goes in the tube that runs from your last prefilter to the "IN" port on the RO housing.

Lowes sells a pressure guage, but the fitting is made of brass. Should this matter?

No - the brass fitting would be inline prior to the RO membrane.

I called Aquasafe (where I purchased my R/O unit) and they guarantee their unit to bring the PPM to < 10ppm, which it does. My water here in Kingwood is 187ppm before any filtration according to my TDS meter.

I believe that unit cames with a 100 gpd (not 110 gpd!) Filtec membrane. If that is the case, this membrane has a 90% rejection ratio. So if your tap water is 187, your post-RO water should be ~19.

Your DI resin will then take it down to 0 or 1.

At what ppm is considered unsafe for the reef environment, or drinking for matter?

Plenty of people use dechlorinated tap water (high TDS) for their reef tanks. They often times have algae problems as well. 19 ppm TDS is much better than 187, and 0 or 1 is much better than 19!

There are varying opinions about drinking DI water. Drinking RO water however is fine and dandy. If you want to do this, install a T in the RO permeate tube between the RO housing and the DI housing. Run a tube off the T and install a small valve there.

Blue

 

[Guest]

Why not try our new sponsor, Buckeye Field Supply?

I bought my unit on ebay and all my refills have come
from him. Reload your own. It is not necessary to buy
the screw cap filter housing, but it is easier to reload.
If you need help opening and closing your filter cartride,
reply to this address. First order the DI resin refills. tCheap!

 

[Guest]

No, I didn't buy my unit from EBay, I got it from Air Water & Ice. I could have swore they said to replace the prefilters every year. But, if you say every 6 months, that's probably not a bad idea - especially since our tap water routinely reads in the 400-450ppm TDS range.

Do you carry filters that will fit the Air Water & Ice units?

 

[AggieBrandon]

Mike,

I think most ro/di units use the cartridges that are around 10 inches or so. The replacements I got from buckeye fit perfectly.

Brandon

 

[dobber99]

Thanks for the info.

 

[Guest]

mike,
i also got my ro/di from Air Water & Ice and yes, they did say to replace the prefilters every year. in fact, i bought my unit exactly 1 year ago and they sent me a 'reminder' email telling me that it's time for new filters just the other day. i would think that the vendor would recommend buying the filters more often than absolutely necessary.

anyway, just my .02
i'd better get some new filters if 6 months is the official recommended replacement time limit

 

[Buckeye Hydro]

Nothing really "official" about 6 months, but it is a widely accepted rule of thumb. As you say - life span of the filter will depend in large part upon the quality of the water you are supplying, the pore size of the filters, etc...

For your carbon block - check the chlorine capacity of the block and put pencil to paper re the number of gallons (permeate + waste) you've run through the unit.

Russ