RODI micron question

[ReefOcean]

I was looking at the Aqua Pure RODI units and decided to check some reviews. People seem to think they are OK but it seems unanimous that 5 micron sediment filters are like spaghetti strainers. I saw a few recomendations for BRS branded RODI which are only slightly more expensive (albeit you need to pay for shipping) but all of their packaged systems also come with 5 micron filters. So what is the deal? I would assume that BRS would include 0.5-1 micron filters in their packaged units if they were so necessary. Is 5 micron good enough?

[Myka]

Check out the "New to the Hobby" forum. I just posted an article about RO/DI systems a few days ago that talks about filter choices.

I like to match the microns of the sediment filter to the microns of the carbon filter. If you want to use 1 micron carbon filter then I would choose a 1 micron sediment filter. If the sediment filter clogs up too fast, then you can either a) deal with it because those filters are inexpensive, or b) add a second sediment filter so you can use a 5 micron ahead of the 1 micron. I do prefer to use 1 micron filters. 1 micron carbon filters are much more effective than 5 micron carbon filters.

[ReefOcean]

Check out the "New to the Hobby" forum. I just posted an article about RO/DI systems a few days ago that talks about filter choices.

I like to match the microns of the sediment filter to the microns of the carbon filter. If you want to use 1 micron carbon filter then I would choose a 1 micron sediment filter. If the sediment filter clogs up too fast, then you can either a) deal with it because those filters are inexpensive, or b) add a second sediment filter so you can use a 5 micron ahead of the 1 micron. I do prefer to use 1 micron filters. 1 micron carbon filters are much more effective than 5 micron carbon filters.

Yeah I read that too, the carbon filter get's clogged and contaminated with stuff not caught by the prefilter. I would assume that yes, a 1 micron filter would be better since they can catch much smaller particles, thus creating a much more pure water. But in your opnion, is it really that much better? What sort of difference in TDS should one expect? What is the 1 micron filter catching that the 5 micron isn't?

Honestly I would just like to buy one of these cheaper systems and be done with it. But if having one of these units is the same as not having one at all, I would probably have to buy seperate filters etc and set up my own unit.

I will check out your article. Thanks.

[ReefOcean]

So I read your aticle and I am thinking I should just buy a package and replace one of the filters. Seems pretty easy.

[Myka]

So I read your aticle and I am thinking I should just buy a package and replace one of the filters. Seems pretty easy.

That's what I would do. You can buy a 1 micron sediment filter for $10 or less. How many microns is the carbon filter that it comes with?

[StirCrazy]

Watch what you buy and read the fine print, there are different ratings for filters, normaly you see 1 micron and it is an average size rating, this means there will be some bigger getting through also, what you want to look for is a 1 micron absolute rating, which means nothing bigger than one micron will get through.
Also, chloramins can be trickey and a normal carbon block filter is not enough, where two is. The dangerous part is the cl getting through and that is what kills your membranes.
When i buld a ro system from a area that uses them in the water system i put two carbon block filters befor the membrane which are both 1 micron absolute, befor that i put a 1 micron absolute sediment filter. Thoes are all standard 10x4 filters, on my own i went a step further and i bought a 10x6 housing and i use a graduated 25 to 1 micron filter in that as a prefilter. That alone has increased the life of my normal sediment filter and carbon blocks by about 4x.

I also do not use di filters anymore as unless you have realy bad water or your ro isn't working properly, your waisting money, if your tds is 0 befor your di, you dont need it so let it burn out then use the housing for a second carbon block. Other people will swear by them, i grew up in edmonton but i don't know the water there anymore so maybe you need it maybe you dont.

Things to keep in mind is you have two goals, to protect your ro membrane its self, and to produce the best water you can. A few years ago people were replacing membranes every year, we found this was from the switch from chlorine to chlorine/amonia mix, the amonia binds to the chlorine so it doesnt disapate in the water system and is harder to remove, which allows the citys to run lower chlorine levels and still have it last all the way to your kitchen tapat levels that provide proper protection. What we found was that one carbon block filter did remove a lot of it, but what it didn't remove was broke up into cl and amonia, bu adding the second carbon block you were insuring anything that made it through your first one was taken care of and when your first one started to be exhausted the second one also protected against that. The result for me was a extension to 5 years life on my ro membrane.
Steve

[Myka]

I also do not use di filters anymore as unless you have realy bad water or your ro isn't working properly, your waisting money, if your tds is 0 befor your di

Steve, ammonia from chloramine goes through the carbon and RO membrane untouched. The DI is what takes care of the ammonia. Also, a person would have to have very low TDS out of the tap to have 0 ppm TDS after just RO.

Most people run their RO membrane until the water coming out of it is 10-15 ppm TDS. The DI will polish that up, extending the useful life of the RO membrane.

Sent from my Dungeon using mad Ninja Skillz.

[StirCrazy]

Steve, ammonia from chloramine goes through the carbon and RO membrane untouched. .

the Carbon breaks the bond and removes the CL, but the ammonia still carries on. the RO membrane its self will reduce ammonia to very low levels, depending on the PH of the water, design of the membrane and such, I supose if you still have residual ammonia you coudl use a DI, or other softener type ion-exchange. but to say the ammonia carries on throught the RO untouched is not right at all.

Steve

[Myka]

the RO membrane its self will reduce ammonia to very low levels, depending on the PH of the water, design of the membrane and such, I supose if you still have residual ammonia you coudl use a DI, or other softener type ion-exchange. but to say the ammonia carries on throught the RO untouched is not right at all.

Steve

I have seen this in my own fish only systems that get RO with no DI filtering. After carbon my tap water usually has about 2 ppm ammonia. After the RO membrane there is still 2 ppm ammonia that I use a detoxifier on. I'm using dual 150 gpd 98% rejection membranes.



Sent from my Dungeon using mad Ninja Skillz.

[Myka]

the Carbon breaks the bond and removes the CL, but the ammonia still carries on. the RO membrane its self will reduce ammonia to very low levels, depending on the PH of the water, design of the membrane and such, I supose if you still have residual ammonia you coudl use a DI, or other softener type ion-exchange. but to say the ammonia carries on throught the RO untouched is not right at all.

Steve

Sorry, I am mistaken. I was thinking about it more today, and my fish only systems bypass the reverse osmosis membranes. You are correct, the RO membrane will reduce ammonia based on pH coming out of the carbon filter.

[Myka]

I was just digging up some links for another thread, and came across Randy Holmes-Farley's comments on what passes through RO membranes:

"However, at the small end of the spectrum a number of compounds can pass through a reverse osmosis membrane to some extent and are, therefore, of concern to reef aquarists. These include carbon dioxide (CO2), ammonia (NH3), hydrogen sulfide (H2S, especially a concern with well water) and silicic acid (http://www.gewater.com/library/tp/696_A_Study.jsp) (Si(OH)4, which is the uncharged and predominate form of silicate at pH values below 9.5). All of these should be trapped by a functioning DI resin (discussed below), but can still be a concern."

Obviously, there isn't a 100% fail rate with these compounds either though.

[Craigdillman]

Check out aquasafe Canada there to RODI machines are awesome they have quick shipping and solid prices on filters. Got a setup with drinking tap and 4 gallon too off container for round. 185$ ish

[StirCrazy]

I was just digging up some links for another thread, and came across Randy Holmes-Farley's comments on what passes through RO membranes:



yup not 100% in another article by him, he does tests and finds he normaly starts out with about 2ppm and the ro brings it down to about .1 - .2

now in a healthy reef aquarium when you test the water you will probably see 0 as your bacteria will reduce it rather quickly.

now having said all that membran selection is obviously important also, as diferent brands and different construction methods give different rejection ratesof different elements, the rejection rate advertised is just for stabalized salt.

I just reviewed some of my documents and amonia is a trickey one, it can either pass through or be rejected depending on the PH and temp of the water which would explain why I always got 0 amonia out of my RO in Victoria and here in kamloops (city is fed by ro system) I will just post the explanation from my Dow lititure.

"
Dissolved gases like ammonia (NH3) will not be rejected by an RO membrane; however, NH3 is in equilibrium with the ammonium cation (NH4+), as defined by the following equation:

NH3 + H+ <---> NH4+
Decreasing the pH and/or temperature will convert NH3 to NH4+, which is rejected by the FILMTEC RO membrane.
For example, as long as the temperature and pH are less than 40°C (104°F) and 7 respectively, more than 95% will be present as NH4+ and the rejection should be better than 98%. However, if both parameters are allowed to increase, the amount of ammonia will also increase, accompanied by a corresponding decrease in rejection by the RO membrane. "

so the hardness of your water does make a difference in the rejection, which would lead to the question if your RO runs after the water softener would this help in that area? would be neat to see if some one has one if they could do with and with out testing.

Steve

[Myka]

In my system, pH is 7.5 to 7.8 after the carbon block and I use 72-75F water. I just use a 1 micron carbon block, and it handles all the chloramine and chlorine. I'm going to test ammonia after my RO membrane now - I'm curious how much is getting to my DI resin.

Also of note, NH4 generally isn't toxic to fish, but NH3 is lethal.

[StirCrazy]

In my system, pH is 7.5 to 7.8 after the carbon block and I use 72-75F water.

PH might be a bit high but let me know what your getting, another problem brought up by Randy is the test kits we use are basically junk for lower concentrations and quite often give bad readings, but who wants to spend the money for a good one......

on another note, why is your tap water so hot?




Also of note, NH4 generally isn't toxic to fish, but NH3 is lethal.

ya NH4 has to be pretty high to be harmful, but I think in the big picture, if are talking "top off water" then a little NH3 would be diluted so much then metabolized by the bacteria rather quickly. water changes might be different but if you have high ammonia you can always treat for it just before you mix your salt.

but this has gone way off the rails of ReefOcean's original question about if the Aqua Pure units are good, there all the same, only difference is amount of stages, type of membrain, and the filters. Do you have a link to a picture of the one your using. Also you need to know a bit about your water, in victoria we had a huge algae content in our water, this sucks as it plugs filters real fast, same if you have high sediment content.

now from what I remember (26 years ago), edmenton had medium hardness water. ok so I just looked, the average TDS seams to run between 138 and 170ppm this time of year and they adjust PH to 7.8

if your talking this aquapure company http://www.aquapure.com/aq-products/drinking-water-systems/aqua-pure-drinking-water-filtration-system-ap-ro5500-lf.html

run away and don't look back, propriatary filters that are expensive.

this is the look the system should have http://www.costco.ca//.product.10344948.html?utm_campaign=bazaarvoice&utm_medium=SearchVoice&utm_source=RatingsAndReviews&utm_content=Default

I prefer the clear housings myself. most systems like this one (5 stage ro) are comming with a 5micron prefilter, followed by 2 carbon block filters (thats the 3 on the bottom) then the ro AND A gac post filtration. if you are using it for your tank only then you don't need the tank or GAC stage but the GAC won't hurt anything. mine was basicly this but it had two RO membrans for 320 gal per day and a resin filter instead of the GAC. what I did was add a stage at the beginning which was my 25 to 1 graduated filter, put a 1 micron in the chamber that had the 5 in it and then the two carbon blocks.

any questions feel free to ask, sorry for side tracking this thread off topic so bad haha.

Steve

[NIVLEM09]

Don't mean to high jack this thread but I need some advice.im currently using an API Tap water filter and in the process of purchasing an RO/DI unit,which one do you think is the best and what accessories do I need?im such a noob-apologize to the OP

[Craigdillman]

Best to start your own thread, :)

[Aquattro]

Don't mean to high jack this thread

Then I don't understand. You did. Please start your own, they're free :)