RODI - Which filter(s) do I need to replace?

[Eienna]

I just tested my RODI water, and the TDS is up at 40. >.< Great. No wonder my snails are unwell. Tried flushing the membrane...no reduction. I also tried both bypassing and not bypassing the DI. No response I could see. Gotta charge my phone but then I can get a photo.

 

[AZDesertRat]

You need 3 TDS readings to know for sure what needs replacing. Tap water TDS, RO only TDS before the DI and final RO/DI TDS.
You should replace the sedimet and carbon block filters every 6 months regardless or usage as their urpose i to protect the RO membrane. They have very little to absolutely nothing to do with TDS so the 6 month rule is easiest to remember for them and TDS applies to the membrane and the DI.

What are your 3 TDS numbers?

 

[Eienna]

I'll get the other readings tomorrow (tap and no DI.)
After running a while, it got down to 24. Better, but not good enough.

 

[Eienna]

Bypassing DI: 24
Full RODI: 19
Source Water: 512 (yikes!!!)

 

[ebushrow]

I would replace all of them except the di resin, can't really see if it exhausted by the photo, but just as an aside, the paper filter furthest to the right should be bright white, not orange.

 

[Eienna]

I would replace all of them except the di resin, can't really see if it exhausted by the photo, but just as an aside, the paper filter furthest to the right should be bright white, not orange.

I might replace the resin, too. It's really dark.

I THOUGHT that filter on the right looked a little dirty!

When you say all of them, are you including the membrane in that?

 

[Fin]

IMHO, I would replace all of them, including the DI resin. If you are getting 19 TDS reading of your final product water, I would say the DI is exhausted also. Should be zero. Sounds like you are getting about a 95% rejection rate from your membrane (24 from 512), so that is probably fine. I would change the pre-filters, carbon & DI. My 2¢ anyway.

 

[Eienna]

Otay.
I'm trying to figure out which filter set I should get, since I don't know what came with it...any suggestions on what might work well with my water quality being so bad?

 

[Fin]

Otay.
I'm trying to figure out which filter set I should get, since I don't know what came with it...any suggestions on what might work well with my water quality being so bad?

It looks as though the unit you bought is set up to remove chloramines. Do you know if you have chloramines in your water? This appears to be the set up that it came with, if you want to go back with what comes with that model. If you don't have chloramines, you might not need the extra carbon filter. I am not an expert on this stuff, so others may have different opinions. Go with the consensus, if you get other replies. I don't really like telling people what to buy.

Aquarium Water | Reverse Osmosis | RODI Water | ReefKeeper Water | Aquarium Ro REPLACEMENT FILTER PACK Aquarium Water Guru

 

[Eienna]

It looks as though the unit you bought is set up to remove chloramines. Do you know if you have chloramines in your water? This appears to be the set up that it came with, if you want to go back with what comes with that model. If you don't have chloramines, you might not need the extra carbon filter. I am not an expert on this stuff, so others may have different opinions. Go with the consensus, if you get other replies. I don't really like telling people what to buy.

Aquarium Water | Reverse Osmosis | RODI Water | ReefKeeper Water | Aquarium Ro REPLACEMENT FILTER PACK Aquarium Water Guru

I haven't the slightest idea. Given my water quality, though, there could be anything in it.

Thanks for the link.

 

[NanaReefer]

Send AZDesertRat a PM-he definitely has your answers

 

[AZDesertRat]

If your system is 6 months old or older the sediment and carbon block filters need replacing and I would didinfect the system while it is down.
I would not waste money on so called chloramine carbons, you do not need them as long as you use a good low micron sediment filter and a single 0.5, 0.6 or 1 micron carbon block.
I would turn that empty carbon canister into a second DI for a good dual DI system.

What vendors don't tell you is its not the carbon that removes chloramines, it is good DI resin with good contact time that is the most important piece. A single high quality, low micron carbon block will remove the chlorine portion of chloramines and break the bond with the ammonia portion so it can be removed by the RO membrane and DI resin.

Your DI cartridge is exhausted, way past exhaustion really, it should be replaced when you see anything other than 0 TDS after 30 seconds or so. Your RO membrane is marginal at 95% rejection rate, it should be in the 97-98% range or higher.

To get an idea of how much more efficient your system could be, read this article on the new 99% guaranteed rejection rate membranes and how it makes your DI resin last many many times longer and your water quality better:

FAQ p.2

I use a tested Spectrapure membrane, my tap water TDS is 530-600 and my RO only TDS is between 2 and 3. Imagine how long your DI would last like that.
To be perfectly honest with you, I once owned a AWI Typhoon III and thought it was great until my DI costs started eating me up when I increased reef sizes. My tap at the time was a little higher and the absolute best RO only TDS I could get was 13-15 and 150 gallons per fresh DI cartridge no matter what resin I used. I sold it and bought a MaxCap system and my RO TDS went down to 2-3 and the very first DIcartridge lasted 830 measured gallons and has been over 1000 gallons per cartridge ever since.

If it were me I would compare the cost of a new 0.5 micron sediment filter, 0.5 micron carbon block, new 90 GPD 99% rejection rate hand tested RO membrane, MaxCap DI cartridge and SilicaBuster DI cartridge to the cost of a new MaxCap system either thru Spectrapure or from places like Marine Depot and Premium Aquatics which may be cheaper with their free shipping and frequent sales.

 

[Eienna]

O...kay XD bit much to digest but I'll get it.
Part if my problem is that I get 30psi tops with our water pressure. I'm sure that's not helping.

I'll look into what you mentioned. There's no way I'm buying a new system right now but I'll at least look at it and the mentioned filters.

 

[AZDesertRat]

If you only have 30 psi you don't have enough pressure to make good RO water, 40 psi is the absolute bare bottom pressure to force water through the membrane and the lowest the membrane manufacturers graphs and charts go down to.

A RO booster pump would be your best investment to get that pressure up in the 80 psi range. Your membrane is probably not bad now knowing the low pressure you have. Your RO only TDS will drop dramatically with more pressure.

You might also check to see if your home has a pressure regulator on the incoming water line. It would probably be located wher the water comes into the home from the street or alley. Some municipalites require them and they are almost always adjustable with a straight blade screwdriver or smll crescent wrench to trun the diaphragm in a couple turns. No booster should be needed if this is the case.