# R/O Unit



## justin85 (21 Jun 2013)

I am thinking about getting a R/O Unit to prepare my water for my planted tank although I know nothing about the units and there is quite a lot of different types of R/O units on the market. Seen as there not cheap to buy I want to make sure I get the right one first time around, so can any one suggest a good R/O unit to get or one they you are using please.

Thanks


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## Iain Sutherland (21 Jun 2013)

best to avoid RO unless you are sure you need it as its costly on waste water, however if you do need one all of these are good just choose a size.
Reverse Osmosis (RO) Systems and Water Filters, Pure Water made in the UK
be aware you may need a pump to run along side to reduce waste and speed up production.


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## justin85 (22 Jun 2013)

I was considering it, not sure if I actually need it. My tap water pH is 7.5 and the tank water will be at 6.5 I think ada aqua soil keeps it at, I get lots of algae on my cichlid tanks so not sure if I have high phosphates but algae is something I want to keep away at all costs. I was doing some reading about R/O units and you right they can be costly in all area's really, so kinda reconsidering it now.


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## Iain Sutherland (22 Jun 2013)

Your water isn't the cause of algae it's the quantity of light you fire at the tank you should look at.  Unless you ate trying to change water chemistry for the benefit of the fauna I'd advise against RO, it's costly and can causes more work


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## ian_m (22 Jun 2013)

High phosphates do not cause algae or else everyone who doses EI would have monsterous algae problems.

You need to locate what is causing your algae, RO water will not cure algae. In fact will probably make it much much worse if you don't take great care with nutrient and salts dosing.


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## ceg4048 (22 Jun 2013)

You are making a huge mistake. Phosphate doe not cause algae, and using RO water will not save you from getting algae. The more phosphate you have the less likely you will get algae. Also, the pH is completely irrelevant within this context and you will cause more problems than you will sole trying to micromanage pH.

Heading for trouble...in the fast lane...

Cheers,


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## justin85 (22 Jun 2013)

Thanks for the replies. Very helpful! I was under the impression phosphates helped algae to grow......should have done my home work there for sure. R/O water is not on the cards now after reading the replies and I would never just buy and start using something that effects my water so heavily without asking the question first. The tank isn't even setup yet as I am currently doing a DSM to attach my moss, so just exploring different options.


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## Yo-han (22 Jun 2013)

Phosphate does help algae to grow. They need it just like plants. BUT they do not cause algae. Like mentioned before, algae grow when something is short in a tank, not when something is in excess. This is very important to understand for a planted tank. A non-planted cichlid tank however does not need phosphate so keeping it low is not a bad idea. But again, it is not the cause of the algae!


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## ceg4048 (22 Jun 2013)

justin85 said:


> I was under the impression phosphates helped algae to grow


99.99% of all living things on the planet grow more when given phosphate. PO4 is extremely important because it is the active ingredient in an enzyme that produces energy for living cells. Because of it's high energy, PO4 is also used in critical locations of the DNA molecule.

The fundamental difference is that plants need 1000X more PO4 than algae do. Algae really do not care whether there is a lot of PO4 available or not, but plants care, especially if the tank is CO2 injected. When that happens the plants then need about 10,000X more. So think about what happens if you restrict PO4. Which organism will fail first?

Good plant husbandry is all about doing the things that are good for plants FIRST. When you take care of the plants' needs they become healthy, and when plants become healthy then algae goes away. So this is how you need to change the way that you think about the relationship between the two. You will never starve algae to death before starving the plants to death. Algae can grow in straight RO water but plants cannot. Therefore it makes no sense whatsoever worrying about whether algae need this nutrient or that nutrient, because whatever nutrient algae need plants need far more of and will suffer more if the nutrient is missing.

Cheers,


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## justin85 (22 Jun 2013)

ceg4048 said:


> 99.99% of all living things on the planet grow more when given phosphate. PO4 is extremely important because it is the active ingredient in an enzyme that produces energy for living cells. Because of it's high energy, PO4 is also used in critical locations of the DNA molecule.
> 
> The fundamental difference is that plants need 1000X more PO4 than algae do. Algae really do not care whether there is a lot of PO4 available or not, but plants care, especially if the tank is CO2 injected. When that happens the plants then need about 10,000X more. So think about what happens if you restrict PO4. Which organism will fail first?
> 
> ...


 


Thanks for that post! very informative and clear. I guess that I seen amazing tanks with healthy plants and read they use R/O water and thought "maybe I should do the same" before asking the more important question of "Do I need to use R/O water"  I am not going that route now, but I have still found this thread very helpful indeed.


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## foxfish (22 Jun 2013)

Although I agree with the majority of comment on this thread - there is no doubt that some of the top scapers do use RO water!
I have been considering using it myself as there is only one real way, in my mind, to find out if it will make any difference to my tank?
I have never bothered in my planted tanks before as it seems so wasteful & unnecessary but perhaps it is time....


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## ceg4048 (23 Jun 2013)

Also, many of the top scapers think that nutrients cause algae. Many top scapere believe their test kit results, and, many top scapers suffer algal blooms. Finally, many top scapers use tap water. Therefore one cannot easily correlate RO with success, but it is a tool that can be used for specific issues.

I completely agree that RO should be tried to see the differences, and that depending on the type of fish, the local municipality, and the plants in the tank, there can be an improvement. However, the purpose of the responses in the thread is to prevent inexperienced hobbyists from falling victim to the second most famous blunder in human history, i.e. that of blaming their problems on water parameters.

Hobbyists are encouraged to learn how to grow plants successfully and algae free with the water they have first, and by using the fundamental principles of plant and fish husbandry, then try RO. That way, success or failure can be better correlated with the type of water being used, instead of being a random occurrence. The exact same argument goes for any object or device one wishes to evaluate. Become a good plant grower first and foremost. That is the only way to truly validate the analysis of the object being evaluated.

Cheers,


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## Yo-han (23 Jun 2013)

Not a top aquascaper but I do use RO myself. But it depends on the tank and the parameters of your tap water. Plants take up nutrients easier in soft water than in hard water. With a KH of 20 out of the tap -> use RO. I've a KH of 6 out of the tap so I use almost no RO in my 400L. But in my small tanks I keep soft water fish and I use 75% RO to reduce KH and hope to increase spawning. Same thing applies when growing Tonina or Eriocaulon species. Easier in soft water.

So my advise would be to use RO only to set KH if you've a specific purpose. Don't bother about other things.


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## ceg4048 (24 Jun 2013)

There is little evidence that nutrient uptake in plants is easier in soft water than in hard water. That has to be the product of someones dream. If anything, the nutrient uptake rate typically increases with increasing hardness. There are two basic mechanisms of nutrient uptake in aquatic plants:

The first is a passive mode where the concentration of the nutrient ion exerts an osmotic pressure against the leaf. The higher the concentration, the higher the pressure. The osmotic pressure of a nutrient ion is completely independent of the other ions in the water. Therefore, it doesn't matter whether the water is hard or soft. 10ppm NO3- is 10ppm NO3- regardless of whether that NO3 is in RO water or in water with KH 20.

The second mode is an active mode where there are specific enzymes dedicated to attract and hold that nutrient molecule. The enzymes are embedded in the outer membrane of the cell and are usually capable of distinguishing between their target ion versus random ions, although there may be some exceptions. So, even in hard water which has an abundance of ions, the enzymes capture the nutrient ions of interest and allow them to pass through the outer membrane layers unimpeded. A higher ionic content in the water actually pushes the target nutrient ions away towards the receptor enzymes.

Then of course there are the roots, which have similar electrolytic processes for uptake.

So no one actually knows why Tonina has difficulty in hard water because we don't know what we are measuring, and it could easily be that Tonina has a negative response to some compound which is typically found in hard water but which may actually have nothing to do with hardness, or it may be responding to only a specific characteristic of the hardness.

Also, KH really is not the same as hardness, so this causes even more confusion. Your KH test kit doesn't actually measure the Carbonate content of the water. It measures the water's ability to sequester/neutralize acid (H+), which, Carbonate and bicarbonate are famous for, but which many other ionic species (Na+, K+, Ca2+, Mg2+, Cl-, SO42-, and NO3-) are also quite capable of to a greater or lesser extent depending on their concentration within the water column and depending on their interaction with other ion species . The ability of water to sequester acid is referred to as alkalinity. So your KH test kit measures alkalinity because it cannot identify carbonate or bicarbonate from the myriad of other ions in the water which affect the behavior of acid.

That's why there is so much variation in response characteristics in different tanks. Two people can measure KH to be exactly the same in different locations, one tank has more Carbonate/Bicarbonate than the other. If the effect on a fish or plant is related to the level of Carbonates then there needs to be some other measuring device to determine what the actual Carbonate level in the tank is in order to make a rational assessment. If the fish or plant is sensitive to one of the other negatively charged ions that affect alkalinity you will not know what that ion is from a KH test kit.

There is a similar ambiguity with GH test kits because they can NOT differentiate between Magnesium and Calcium. So if a fish or plant has a negative response to Calcium, but not to Magnesium, you need more specific equipment to determine what portion of the GH Calcium contributes to. These are yet more reasons why hobby grade test kits suck. 

Cheers,


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## DrRob (26 Jun 2013)

To throw in another experience, and to agree wholly with ceg, I use RO, not for the reasons listed above but because our tap water is near illegal with farm run offs getting into the supply (ammonia, DOC and all sorts of fun things in it, we don't drink the stuff given half a chance because of the taste, but it is inside legal). When I first moved to RO, if anything my algae problems got worse. The fish looked healthier for it all and started to breed, but the algae worsened, as did the plants. Getting the light down and the fertilisers up have largely wiped out most of my algae problems though.


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