question about using RO units

[Bravofleet4]

This question is related to another one I've posted in the freshwater noobie forum but I haven't gotten replies to it. Nevertheless, it's not exactly the same and I could use help.

I've moved back home away from my dorm now that summer has started. We have a water softener and I've been getting water from the water filter. Several questions. First, do I need to add fertilizers to my planted freshwater 10 gallon tank since the water filter is supposed to remove most impurities? Second, will the loss of minerals mean that use of DIY CO2 is going to dramatically drop my pH further? Third, can I just get water from the sink (which would contain NaCl)? If not, then do I need to invest in an RO/DI unit (eventually I want to purchase a much larger tank). Right now the water filter produces only a small amount (<5 gallons per day) of water each day and it takes so long to fill up my tank.

 

[Riiz]

Sort of confused, are you using a water filter that gets water first from a water softener?

But just incase you are, and your water filter does remove all minerals and such from the water, then you will need to add nutrients to a planted tank. And yes softened water, will lose its pH buffering capacity and CO2 will need to monitored so the the pH is not too low for your fish/plants.

But usually their is one water line or tap from a home softening unit that is not softened, which might be better to use, because that water wont be loaded with Sodium from the softening process.

 

[jones57742]

We have a water softener and I've been getting water from the water filter.

Bf:
The water softener is adding salts to the home water and the salts are probably NaCl and KCl (look on the salt bag).
Unless the "filter" to which you refer is RO/DI you are increasing the concentration of salt in your tank water with each top off and partial WC.

First, do I need to add fertilizers to my planted freshwater 10 gallon tank since the water filter is supposed to remove most impurities?

Yes.
Due to the size of your tank Seachem liquid ferts are probably economically feasible.

Second, will the loss of minerals mean that use of DIY CO2 is going to dramatically drop my pH further?

Bf: although you have done your research IMHO you are barking up the wrong tree here. At concentrations above 30, which you could easily generate in a 10G tank with DIY CO2, the CO2 can become toxic or lethal to your fish. I would not do this one but would just experiment with the dosage rates of the liquid ferts in order to produce good plant growth with the generation of algae.

Third, can I just get water from the sink (which would contain NaCl)?

No.
Refer to the first response in this post.

If not, then do I need to invest in an RO/DI unit (eventually I want to purchase a much larger tank).

I would not if the current filter is RO/DI as a nice four stage RO/DI unit would not be cost effective for a 10G tank.


Bf: Two additional items.

Please purchase and use a liquid reagent test kit. I use TetraTest but many folks prefer other kits (You can Search this Forum for recommendations).

If your existing "filter" is indeed RO/DI I doubt that that the filtration media has ever been changed and probably appears to the color of as well as posses the viscosity of low grade crude oil, ie. it is not functioning.
My RO/DI manufacturers recommend that the primary cartridge be replaced bi-annually that the secondary cartridges be replaced annually (I replace mine more frequently).

TR

 

[cubequeen]

I would like to throw in the suggestion that you use potassium chloride in your water softener, if possible. I think most water softeners can use either sodium chloride or potassium chloride, but you might want to check your manual or check with the manufacturer. The added potassium will be good for your tank.

Also, just my 2 cents, but in my opinion RO and DI is overkill. When I first got my RO/DI unit I would detach the DI for drinking water, then re-attach it for the fish. I tested both the RO and the RO/DI water and could detect no measurable difference in the phosphate level and very little difference in the total dissolved solids. Even without the DI the water comes out at 9-11 TDS. So now I just use RO for everything.

For a 10-gal tank I would just go the grocery store and get water from the water machine, if you can find one that does RO and not just filters. Or buy distilled water. But if you're going to move up to a larger tank, I'd definitely invest in an RO unit. Shlepping those water jugs back and forth to and from the grocery store gets to be a real drag after while.

 

[Riiz]

For a 10-gal tank I would just go the grocery store and get water from the water machine, if you can find one that does RO and not just filters. Or buy distilled water. But if you're going to move up to a larger tank, I'd definitely invest in an RO unit. Shlepping those water jugs back and forth to and from the grocery store gets to be a real drag after while.

Some of those are a rip-off, I used a decently new machine by my house to see it if was really R/O water. I got it home and tested it and it the same water chemistry as my tap. So it might be better to goto a LFS and buy their R/O water, since 10 gallons, wont cost more than $4-5 total.

 

[Bravofleet4]

Thank you for all the help!

I think I will take Riiz's suggestion and look into whether or not there is a line before reaching the water softener that I can draw water from. Would using a non-lead garden hose also give me the same water as tap water if I can't find one? To be honest, I do not want to spend that much money even if I get a much larger tank like I'm planning to.

I would like to use follow queen's suggestion that we use potassium chloride instead of sodium chloride but I don't really live here anymore. I mean that in the sense that I stay home only 3 months of the year nowadays. It's a shame because it would've saved me from having to dose potassium for my plants.