RO - RO/DI Water

RO is fun

I use RO for several years and I like it. It gives me the option to control all the elements.
With tap water we never know what is going on. There could be ions of high concentrations that we have no test kit for.

Last time I tried tap water the snails looked dead for a week.

There is no issue with the operation cost. The whole system needs one $3 10 um cartridge and one $10 carbon cartridge a year. The cost of running water is $1 for 60 gallon of pure water. The main cartridge works for 5+ years.

This mix I use, is to recreate balanced levels of Ca2 and Mg2. This is used for a long time, since DI was introduced to breed Discus.

3.0 g CaSO4
1.0 g CaCl
1.5 g Soda
1.0 g MgSO4

Final concentrations can be tested by TDS meter for breeding or by regular Calcium test kit for growing aquatic plants.

Thank you,
Edward

Well it's been a month now since I have posted this poll and about 2 months since I started using RO/DI myself. It sure is very nice to be able to control water parameters to your liking and experiment with different levels in different tanks, it also makes killing snails very easy by lowering your GH and KH to the point where their shells become weak and brittle. But most of all I have noticed in general that my tanks are cleaner, spot algae is less than what it used to be so that is nice. The biggest advantage is probably to the fish in my case as my tap water has heavy metals in it which do a great job at killing my fish if I use a water conditioner that does not treat for heavy metals, I found that out the hard way. Now I don't use any conditioner at all.

I bought my 100gpd filter from aquasafecanada (ebay seller) for around $150 with the 3.2 gallon container (a must IMO), shipping and a digital TDS meter. That's quite cheap and based on what I hear about replacing filters, the only one that really costs a lot is the RO membrane and DI filter, both of these have a nice long life span and in 4-5 years I'm not sure if I'd spend $80 on new filter elements or just buy a new unit from them again, price difference is not a lot if you think about it (excluding the TDS meter and 3.2 gallon container). Plus I now have very good tasting water and ice cubes

Considering what I spend on my tanks each year it's not very difficult to justify $150 on pure water.

Giancarlo Podio

Good question. I think it's a much debated topic, you hear both sides of the story anywhere you go. I've been drinking RO/DI for a couple months now and am still standing

I think most people will save their DI filter because it doesn't last long and regular RO water is more than sufficient for drinking. If I see my DI filter doesn't last long I may do the same myself. I'll look more into the DI issue just in case I shouldn't be drinking it...

Here's the exact same unit that I purchased on ebay for 1/4 of the price:
http://www.cantares.on.ca/ro/

Here's a thread on the drinking topic:
http://www.finishing.com/156/65.html

Giancarlo Podio

Art_Giacosa said:

Edward,

I'm curious why you add CaCl and CaSO4.

Click to expand...

I used to breed discus before plants took all my free time. First, there was an ion exchanger DI, made of cati and ani to purify the water. I still have HCl hydrochloric acid and NaOH sodium hydroxide at home. These were needed to regenerate the functionality of the DI. From this experience, I know how unsafe DI is to maintain and to drink.

The water purity produced by a DI is 10x better then the distilled and 100x then the RO, but it doesn't matter for the plants.

DI, cati/ani 0.1uS TDS
Distilled 1.0uS TDS
RO 10uS TDS

Back to your question, waters stripped of minerals need to have restored basic living conditions for the fish eggs to develop and for the fry to survive. It's all about balance of salt ions, causing osmotic pressure on living organism. Balance of Ca:Mg:Na:Cl. This is why I am still using the discus breeding formula to grow aquatic plants. If it's good for discus, must be good for plants. And it works just fine.

It's a mix of dry minerals:
3.0g CaSO4
1.0g CaCl
1.0g MgSO4
1.5g Soda

For discus keep adding until desired conductivity uS TDS is reached. For plants until measurable Ca2+ .
For an automatic continues RO water change, this kind of dosing makes it difficult to keep stable levels. So I started experimenting with dolomite as Tom Barr suggested. It is a mineral made of CaCO3 calcium carbonate and MgCO3 magnesium carbonate. http://mineral.galleries.com/minerals/carbonat/dolomite/dolomite.htm . This dolomite might replace the discus formula for plants if it proves to be working.

Thank you,
Edward

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2005 01 05
Dolomite increases TDS and KH too much. Ca and Mg is there, but the KH is out of control.

Hi Jason

There is no point using DI for planted aquariums. The RO cartridge already removes 90 – 99 % of all dissolved elements. Here is how it works:

500 uS TDS very hard water
300 uS TDS usual tap
10 uS TDS RO
1 uS TDS distilled water
0.1uS TDS DI

RO water does not have any GH or KH. You need to either mix it with tap water or add Ca, Mg and KH. Plants need Ca and Mg for healthy growth.

Edward