DI WATER

[scatman]

Will DI water be good enough to keep a reef system or must it be R/O .

[RnB]

It would be fine, but you would use a lot of DI resin/gel/thingies thus may be more expensive in the long term if you are making a lot of water.

The RO purifies the H2O and thus the DI resin lasts a long time.

RO membranes last a long time if looked after (correct pressure used, some say backflush them, others disagree, commercial guys say backflush but also said that at my 50L per week rate the membrance not clog that much anyway)

I seem to get about 1 year out of $60 of DI resin and make at least 2500L per year. the RO membrance cost about $120 from AI and should last for years.

If you are running a nano then probaby no problems

[nodle]

One more thing is that DI will not remove Chlorine or other Chloride products so you will need to run the water through a carbon filter first. I looked at this before buying a RO/Di unit. This will also help to remove some of the Organic meterial from the water and help to prolong the life of the DI filter. A Carbon filter can be easaliy made with some pvc pipe fittings and a couple of small bags of Activated Carbon. Pm me if you want a plan and i will do a quick drawing of one and PDF it for you.

Dave

[scatman]

Thanks for that. I think RO/DI is the way then. My only concern is that i stay on a rural property with tank water with weak water flow. Every 2/3 days i have to scrub my bath as it gets a blue green tinge so i wonder if it will affect the filters more

[nodle]

You may have some probems with an RO unit as they require good water pressure to push the water trough the membrane or at the least the amount of water delivered from the unit would be well below the rated size of the unit. The other option is to get some 10-5 micron filter canesters and plumb these in before a Carbon filter then into a DI filter.

The amount of desolved organics in the water will be high if you are getting algea build up on the bath every two to three days and this would be hard on the RO unit and filters but also means that there is proberly no to very little Chlorine in the water.

Here is the Carbon filter you can make yourself and can also be used as a carbon filter in the sump if you change the inlet and outlet fittings to suit a powerhead.

Dave

[RnB]

I really suggest a vist to Anthony Preston Ltd

167 Moore St Howick Auckland 09-534 5127

They have everything in this RO/DI including the DI resin by the kg.

It may be cheaper to buy a cannister rather then try and make one.

The other option is to buy from US mailorder everything you need.

Anthony Preston can sell you membranes, flow restricters etc as replacements later if you wish.

I was looking online recently and there are some good deals out there in mail order land. Trademe has RO systems for sale sometimes as well

you will have trouble making RO work through tank pressure only. Try and borrow a pressure guage from a local farmer etc to test what you have now.

There are lots of downloadadble pdf files from the RO membrane guys regarding required pressure rates etc. In my experience getting the correct flow restricter is also important.

Happy to show you my installation if you are interest, live central AKL.

[scatman]

thanks for all your help. I am going on Holiday and when i am back i will look into this

[reef]

If you are on rainwater then DI is the best option, RO will waste too much water about 4 to 1.

DI filters water better than RO, But RO is used on town water supply as it last much longer than DI.

I would get a carbon filter and two di canisters in a row.

[jetskisteve]

since when does DI filter better than RO ?

[reef]

Info from the net

De-ionization (DI) units come in two basic varieties: mixed bed and separate bed. Two chambers are used in separate bed units, one for anion resins (to filter negatively charged ions), the other for cation resins (to filter positively charged ions). Mixed bed units use a single chamber with a mix of anion and cation resins.

DI units are 100% water efficient with no waste water. They are typically rated in terms of grains of capacity (a grain is 0.065 grams). Once the capacity of the unit is reached it either needs to be replaced or recharged (using strong acids and bases). Recharging is normally only an option for separate bed units.

A quick check of the local water quality reports (normally available free from the water supply company) will reveal the water purification capacity of a given DI unit. For example, if a unit rated at 1000 grains is purchased and the local water supply has a hardness of 123 mg/l (Missouri River, USA), then the unit capacity is (1000*0.065)/0.123 = 528 liters = 139.5 gallons of purified water.

Water production rates for DI units varies, but is typically around 10-15 gallons/hour.

Note that some contaminants captured by a DI unit may "break through" long before the unit indicates its capacity has been reached. Silica is a classic example. What happens is that silica is loosely bound to the resins initially, but is replaced by stronger binding materials like carbonates as the resins become exhausted. The use of two DI units in tandem, as mentioned elsewhere in this FAQ, helps to eliminate this problem.

1.1.3 RO Filters

Reverse osmosis (RO) units are normally based upon one of two membrane technologies: cellulose triacetate (CTA) and thin film composite (TFC). CTA based systems are typically cheaper and do not filter as well (90-95% rejection rates). TFC based systems cost more but have higher pollutant rejection rates (95%-98%). CTA membranes break down over time due to bacterial attack whereas TFC membranes are more or less impervious to this. CTA units are not recommended for reef tank purposes. TFC membranes are very sensitive chemically to the chlorine found in most water supplies. It is therefore very important to regularly replace the carbon block pre-filter associated with all better-grade TFC systems. TFC membranes are damaged by chlorine so a properly functioning GAC prefilter is mandatory.

RO filters work by forcing water under pressure against the membrane. The membrane allows the small water molecules to pass through while rejecting most of the larger contaminants.

RO units waste a lot of water. The membrane usually has 4-6 times as much water passing by it as it allows though. Unfortunately, the more water wasted, the better the membrane usually is at rejecting pollutants. Also, higher waste water flows are usually associated with longer membrane life. What this means in practice is that 300 gallons of total water may be required to produce 50 gallons of purified water.

Like any filter, RO membranes will eventually clog and need to be replaced. Replacement membranes cost around $50-$100. Prefilters are often placed in front of the membrane to help lengthen the lifetime. These filters commonly consist of a micron sediment filter and a carbon block filter. The micron filter removes large particles and the carbon filter removes chlorine, large organic molecules and some heavy metals. Of course, the use of prefilters makes initial unit cost more expensive but they should pay for themselves in longer membrane life.

RO units are rated in terms of gallons per day of output with 10-50 gallon/day units typically available. Note that the waste water produced by a RO unit is fine for hard water loving freshwater fish such as Rift Lake cichlids. Some route the reject water to the family garden.

The ultimate in home water purification comes from combining the two technologies and processing the water from an RO unit though a DI unit. If a very high grade DI unit is used, water equivalent to triple distillation purification levels can be achieved. Since the water entering the DI unit can be 50 times purer than tapwater, the DI unit can process 50 times as much before the resins are exhausted. This significantly reduces the replacement or recharging cost of the DI unit. Using two DI units in tandem, moving the 2nd in as a replacement for an exhausted 1st unit, and replacing the 2nd unit with a new unit will insure that no undesirable elements "break through" the exhausted 1st unit and enter your supply.

If only one filter can be afforded, and waste water is not a concern, then it is recommended that a TFC RO unit with pre-filters be purchased. If waste water is a concern, or if only a small quantity of make-up water will be required (say, for a single 20 gallon tank), then a DI unit would be the preferred choice.

City water is unstable. Many cities modify their treatment process several times a year, dramatically changing its suitability for reef usage.

[jetskisteve]

You could have linked to a site rather than copy & paste-Thanks

[suphew]

Are you sure the blue/green colour in your bath isn't copper, what's your tank made out of? Seems strange to me that a bath would change colour that fast from algae/mould? I assume your bath isn't sitting full the whole time, if it is install a good cannister filter and add some plants, that will clear up the algae in no time!

[Pies]

You could have linked to a site rather than copy & paste-Thanks

Steve we have been though this with Alois already. If he cuts and pastes it, and its turns out to be incorrect he says "i didn't actually write it its just a cut and paste, I wasn't wrong'.

Piestirer

[reef]

Steve we have been though this with Alois already. If he cuts and pastes it, and its turns out to be incorrect he says "i didn't actually write it its just a cut and paste, I wasn't wrong'

MARK ELLIS (aka PIES)

If i had to link in all the information that you give that is incorrect , i would fill this whole forum. So please used you brain before typing.

I was trying to help.

And for your information , Ph George at Anthony Preston and he will also tell you that DI is better that RO. But there are reason why RO is used on Town water supply.

Take a cure for your whitespot and spare us the Dribble

[Pies]

Alois

If i had to link in all the information that you give that is incorrect , i would fill this whole forum. So please used you brain before typing.

Really? I do use my own brain, and write things myself, if I cut and paste I site the source, I don't try and pass it off like I wrote it myself, and then use it as defence when i'm wrong, unlike you. Also unlike you I don't edit my posts after I write them in a weak attempt to retract what i've said.

Take a cure for your whitespot and spare us the Dribble

If we want to talk about dribble lets look at this:

For me, reef keeping is the final frontier after decades of maintaining various aquaria.

.

This is from Alois's tank description on this site. Decades of experance, final frontier. Not only is it compete dribble, it not even your dribble, something else you've cut and pasted.

Almost every thread on this forum that has caused angst or problems have revloved around you and your appauling attitude towards people you have grown to dislike. If you like them (layton) your praise them, if you dislike them (myself) you take every opertunity to attack them. You often jump on this site, stir people up then dissapear for a days or weeks before comming up. For every constructive post you 'write' there is a slew of attacks and rude comments.

As I see it the big problem you have is that you are trying to be a member of the reef community, but also feed off it with your commercial ventures. Like your miracle mud thread, should really be in the commercial section as its a product you sell. Its funny to me to think that 12 months ago (when you were not selling it) you called it 'dirt from someones back yard', now that you sell it how thing change.

You have no crediblity in my eyes, your childish attitude and lies frustrate me.

Mark

[reef]

ONCE AGAIN SPARE US THE DRIBBLE.