# Tap vs. RO/DI



## robitreef (Jan 4, 2005)

I had asked this question in the Flourish Excel thread, but I don't want to hijack it with other questions, so I am starting this thread.

How many of you use Straight tap water in your planted tanks? Are any of you using RO/DI? I used straight tap for my 10 gal at the time with only 15W of light, so algae was never an issue. I soon upgraded to a 29 gal tank that had 110W of PC Flourescents, and when I used tap, I got a serious algae bloom. I wasn't ready to dose CO2 in that tank other then Flourish Excel, so I switched to using RO/DI. The plants I kept weren't really affected (Java moss, Java fern and a few crypts). Now I have a 75 gallon with 220w of PC light and I want to start filling it with plants and want to start using CO2 (from what people tell me I should go with a pressurized unit). I am still using RO/DI, but I would rather use tap then have to keep running to the store to get water. (I am adding an RO/DI unit once my kitchen ever gets remodelled-mainly for my reef tank). However, I don't want to have the problem with algae blooms. Plus I have some fish that come from softer acidic water conditoins (clown loaches, red-eye puffer). I also don't want to have a pH crash if I start dosing the CO2. Please assist.


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## trenac (Jul 16, 2004)

I use straight tap water with water conditioner added. 

IMO, I would not use RO water unless you have bad tap water. RO water contains no nutrients so you would need to add extra nutreints for the plants.

A better route would be to use half RO water and half tap water. This way you would still be getting some nutrients.


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## gnatster (Mar 6, 2004)

Then there is the school of thought to use 100% RO and add in exactly what your plants desire to be in the water. The advantage is you have a known source that will not vary season to season. You can establish a dosing regime and not have to worry if tap water is adding something untwards. The downside is the intial outlay for RO unit and the need to add in a few more items.

I go the 100% RO method. 

Don't worry, I'm sure someone will chime in with mixing 50/50. Ahh the best of all worlds.


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## turtlehead (Nov 27, 2004)

100% ro would require some more money.


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## gnatster (Mar 6, 2004)

100% RO is NOT expensive. The intial expense is the unit, and they last quite a long time. I know of one person heading into 7 years + using the same membrane. The other filters last for quite a while depending on your source water and the quality of the filters. For example. I am on a well, so that eleminated the need to remove chlorine so the carbon cartridge lasts for years. Before the carbon is a 10 micron filter then a 1 micron. The 10 micron has not needed changing in almost a year and thats the one that would go first. Cost to replace, about $5. The only other expense is the products to bring GH and KH to levels I desire. In almost ayear of 40gal a week changed I've almost used a full box of bakeing sode to get KH levels up, I think I paid $0.49 for that box. The substrate I used leaches Ca, so thats a non issue, and I need to dose Mg. $1.99 for a 5lb bag at Wal-Mart. 192g of Mg in 500ml water, dose 10ml a day,11.6 bottles of that mix in 5lb so $0.18 a bottle or $0.00036 a day. So all in all using RO add maybe $10 to may annual tank expense, not including the intial investment. Oh tank size is 120gal and I used MH lighting. Oh MY, RO and MH, its a FW Reef!!


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## robitreef (Jan 4, 2005)

Thanks for the replies so far. Of course I am still nowhere close to a decision as there are good arguments on both sides. I may do the 50/50 route. My main concern was for when I start dosing CO2. Right now I don't add anything to my RO water (well, sometimes I add this liquid called electro-right, which is supposed to add electrolytes and some minerals to the RO water), but I would rather have it there already. The Java moss and fern don't care either way and still grow great. Since I want to add a nice forground of Eleocharis, I thought I would have to begin CO2 additions since I have 220W of light. Keep those opinions/suggestions coming!


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## turtlehead (Nov 27, 2004)

I wasn't saying ro was expensive im meant the things that had to come with it like the buffers and stuff, sorry for the unclear info.


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## plantbrain (Jan 23, 2004)

I've never suggested RO is ever needed except in two cases out of perhaps several thousand.
They had private wells, one with copper pipes and had 2ppm of Cu, the other had salt water intrusion on their well.

Other wise it's redundant to take something out of the water only to add it back again, on a practical level this is simply never needed except in exceedingly rare cases. 

I guess if you enjoy making more work for yourself, providing a reservoir for your water changes, only have a few/one small tank/s etc, it's no biggie.
Initial cost is an issue for many folks, I'd just get a CO2 tank/system, that's cheaper than RO over time. 

I do not know what "bad tap water" is for a planted tank. 
I've had tap water from 20ppm KH to 320ppm, GH's from 30ppm to 450ppm.

Plants tend to do better in the harder waters. You can see this in nature as well as in the tanks. RO taste good, I like them for drinking water, but not my tanks. I like to make the water change easy, then I have less to deal with.
I can change it fast, easy, adjust the temp easily etc.

For many years it was said that plants prefer soft acid water, that we needed RO water, that's simply not true.

Some fish may prefer less KH/GH, this is debatable depending on the species, loaches will be quite fine for decades in harder waters(I can show you some 14" ones living in good hard tap water)

Save your RO water for the Reef and drinking.
Otherwise you are taking the GH/KH out and then adding back, that's not needed. 

What precisely in tap water that might be in excess would be "bad" or otherwise undesirable season to season? Taking a KH reading once in while would solve any of that. Even if that did vary, the amount of CO2 being added is stable unless the system has a pH controller, which is one reason I never use one nor tell others to use them.
Plants will use the same amount of CO2 at 2KH as they do at 4. The rate of CO2 additions is also the same, so I fail to see how the variation woukld be bad unless you did not have "enough", adding a little bit after each water change for GH solves that if there is little GH in the tap.

Seems like lots of work to remove something and then add it back and no gain for the work. What do you gain from that?

Tank's growth, plant density, plant species, lighting, dosing, etc change each week, month, year, how do account for all those variables? I suppose you can test and test and test and then test your test kits as well and spend the $ there.

Seems testing the KH once in awhile and using tap is a much easier way to go and much cheaper, don't forget about all the waste water(90% rejection rate for an average) and pumping cost associated with that well water.

I've never had any assoicated problems with a wide range of tap waters, neither has the entire SFBAAPS group for the last 9 years, we live where there are large variations in local tap water types. It's easy to compare.

Regarding the algae: you will not beat algae by using RO water on a plant tank, it's just that simple. Grow the plants and focus on their needs, for a 75 gal, it's fairly easy, tell me what your GH and KH are, I can pretty much give you an easy routine that requires very little testing except of pH/KH.

Then you can work on the reef tank(Use an refugium BTW) and use the RO for that if you want. Call your tap water companyb up also and see what levels they send for NO3/PO4/GH/KH and their ranges also.

Regards, 
Tom Barr


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## robitreef (Jan 4, 2005)

Thanks Tom, The tap in my area is actually pretty good (Chicagoland-we get Lake Michigan water). It will definately save me the effort of lugging around those water jugs. On another note, is there a water conditioner you could recommend that does not add additonal phosphates into water, while neutralizing chlorine/chloramine/heavy metals?


As for the reef, I have had a 16 gal nano running now for almost seven years and it is thriving. Just a simple Berlin style with live rock, live sand, and skimming, with dosing using B-Ionic. It never was much maintenance (1 gal water change every two weeks with RO/DI).


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## plantbrain (Jan 23, 2004)

One thing that really makes a smaller reef tank run well: largen water changes, 1-2 weeks, 50-70% even.
No testing, not dosing etc.alt cost, but so do all those supp's and a PITA.
It becomes cost effective on larger tanks but even 100-150 gal tanks are still quite reasonable with SPS and Macro algae etc.

Are you looking for a non PO4 due to the reef?
Amquel works well for both, but there's no need to worry about PO4 in a FW planted tank, adding will reduce algae and make the plants grow better. 
Adding PO4 to reef will cause diatom blooms on the glass and sometimes of the corals and rock.

Lake MI water is fairly decent.
Save your RO for the Reef and the drinking.

Here's a cheap simple method for the 75 gal tank:
50% weekly w/c.
Add 3x a week: 1/2 teaspoon of KNO3
/18 teaspoon of KH2PO4
Add 15mls of trace mix(Flourish etc) 3x a week

That's it.

You add 3 things.
Like feeding your fish every day etc.

You can scale this down to the 29 gal as well.

Add enough CO2 to get 30ppm during the day(you can leave it off at night since plants do not use CO2 at night except for one genus of aquatic CAM plants).
Measure the KH, see what pH you need to acheive the CO2 level based on the pH/KH/CO2 table, add enough CO2 to drive down the pH to this level. Do not use anything else to change the pH, it's CO2 you and it's CO2 you should add.

pH stablilty etc plays no role in fish health/tank stability or plant growth at night when using CO2 gas.

Regards, 
Tom Barr


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## gpodio (Feb 4, 2004)

I've always used tap water but when I started with corals I obviously got myself an RO/DI unit. For a few months I ran all my tanks on RO but didn't notice any real advantages, actually the plants were more prone to deficiencies than when I was using tap water which makes sense. The one advantage however I did notice and that was in the reproduction rate of my ancistrus, they seemed to enjoy the change in water chemistry. I'm now back to using 80% tap and 20% RO just to dilute my tap a little and keep KH where I want it, it's the only advantage I get from it.

So if you want a lower KH/GH than your tap water is giving you or you are breeding certain fish that prefer cleaner or softer waters it's a good solution, otherwise it really makes little difference in a planted tank, at least in mine.

Regards,
Giancarlo Podio


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## robitreef (Jan 4, 2005)

The water conditioner would be for the FW tank. Since I use RO for the reef, I only add salt-no water conditioners. I've heard a lot of recommendations on Amquel, so that's what I will use. The 29 gal was taken down to make room for the 75, due the fact that my fish were outgrowing the 29. Thanks again.

On a side note-I do remember having my Crypts crash when I switched using tap to go to RO/DI, when I used to have my 10 gallon. I quickly switched back to tap and they recovered.


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## gpodio (Feb 4, 2004)

One caution about Amquel, this is not what I consider a "complete" water conditioner as it does not remove heavy metals. Now weather you need to remove heavy metals from your tap water or not is another story, but I had to find that out the hard way by loosing all my dwarf cichlids a couple years ago when I decided to try Amquel rather than my usual AquaSafe. Amquel is a great product and I use it when shipping live stock however if your tap water contains heavy metals you may need to use a more complete product.

Giancarlo


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