r/o and di water filter

[scott]

i have a small r/o unit (35gpd). i also use an add on di unit with it. my tap water isn't very hard 4dgh/4-5dkh but the ph is over 10. after going through the r/o and di, the water is as follows: 0dgh, 0dkh, and ph 5.0. the thing is that if i don't use the di unit the ph remains above 10 but the kh and gh are still nondetectable with my liquid tests, why is this? i am assuming that it won't take much to lower the ph with 0dkh. i like using the d/i unit but replacing the resin gets pretty expensiv, probably close to $0.15 per gallon. would using peat to lower the ph be as good as using the di unit?

 

[aspen]

if your water is that soft it won't take a lot of peat to lower the ph of your water. try it and see. there are a lot of hobbiests' websites out there showing the ways that they use it.


rick

 

[_BaDgUy_]

Are you sure the pH is around 10???

It seems kinda high!!

 

[scott]

yeah i'm sure, i have a high range test kit with the highest ph of 9.5 being pinkish purple and the lowest of 7.6 being orange. my tap water turns the test a deep purple(not the band). also i once used a hanna meter and it read 10.2.

 

[fishgeek]

something is binding to any dissolved hydrogen ions leaving you with free hydroxide ions , that is the simple answer for why the water is so alkaline

waht that maybe in water that has very little measurable dissolved products in it , i am not sure

using peat is very much like using a di , peat will exchange certain products in and out of itself
it will soften the water further and will also add acidic compounds to the water

peat would seem a viable alternative the only concern may be the low buffering and tendency for pH fluctuations
though i would assume if your pH is as high as you are reading then something in your water has some quite good buffering capacity

perhaps run a few trials of peat treated tap
peat treat r/o etc
and see how they come out

andrew

 

[aspen]

>>'my tap water isn't very hard 4dgh/4-5dkh ...'

>>'...but the kh and gh are still nondetectable with my liquid tests, why is this?'

aren't these 2 statements mutually exclusive? (both cannot be true.)

if the hardness really is not detectable with liquid tests, i'd be a very happy apisto keeper.

it doesn't take much bufferring to get the ph of very soft water up to 10. likewise it won't take much ph adjustment to bring it down.

i would use the peat and if you are having a problem maintaining a steady say, 5.5 - 6 ph, then add a little buffering to stabilise it.

rick

 

[scott]

RICK,

soryy, i guess i was a little bit confusing in my last post. what i meant is that my tap water is 4dgh/4-5dkh with the ph of 10.2 and after going through the r/o the gh/kh are nondetectable but thwe ph is still 10.2 the di is what lowers the ph. i was just wondering if peat is as good as the di unit because it would be cheaper in the long run

 

[aspen]

ok, i just re-read the part about the d/i unit in or out of the system.

a meter will give incorrect ph readings at very low hardness levels, but test kits are supposed to be accurate. but i'd go back to this statement:

>>'it doesn't take much bufferring to get the ph of very soft water up to 10. likewise it won't take much ph adjustment to bring it down.'

if you have any acid at all, muriatic, phosphoric or even vinegar (acetic acid) try and compare how much you need to alter your tapwater (age it first), as compared to how much you need to alter the gh 0, kh 0, ph 10 water. i believe that you will find that a comparitively very small amount will be required to alter the filtered water, but t may swing around a bit. if so, then you won't need much peat to buffer it to 5.5 or whatever ph the peat is bufferred to. (it may say it on the pkg)

i don't believe that using acid to control ph works too well, at least not ime. peat treated water actually seems to hold it's ph more steady and works quite well when the water is soft.

when playing around with water parms, try and use a tank of cheap sensitive fish, like a couple of established neon tetras or something. don't play around with your good fish. mostly you may experience ph bouncing all over the place till you get something that is stable for weeks on end and repeatable.

hth, rick

 

[scott]

thanks for your answers. i just got a new resing cartrige for the di so i won't have to worry about it for a couple months and i can play around with the peat in the mean time. then maybe i won't buy another cartidge for the di again.

 

[aspen]

aerate the water, it may just contain a bit of co2. with an ultra low kh a little co2 will do a lot.


rick

 

[scott]

if i let the tap water sit for a few days with aeration the ph drops somewhere into the 8's if i remember correctly. i haven't tried it in a while since i got the r/o + di unit about 18 months ago. i am considering the use of peat now because of recent additions to my fish room the 35 gpd from my r/o doesn't allow me to do as many water changes as i would like. its either start figuring out the use of peat or upgrade my r/o unit. i have about 150 1 - 1 1/2 inch cacs and 100 1/2 - 1 inch veijita right now so i possibly could use the procedes from selling those to get a new r/o as long as i can hold out until they get a little bigger. on the other hand, if it's not alot more work to use the peat i could use that money for something else (new car........hahaha)

 

[aspen]

ooops i don't know what i was thinking about co2 RAISING ph. it doesn't do that, the presence of co2 LOWERS ph. doh!

i throw a few cups of peat into a big pot of water and boil it on the stove for an hour. i turn the heat off allow the peat to settle for a while, then pour the liquid into canning jars hot, put the lids on and let it cool. i dump the used up peat into the garbage. i store these jars of 'home made peat extract' till needed. i add as much as i need directly into the fish tank after a water change checking ph as i go, a bit at a time. even with tapwater, the effects are noticed, but not as much as in softer water. you coud try it in your change water first, but it is pretty safe, once you get the right amount in a sample of water, the recipe stays the same. water will turn tea coloured brown.

there is a lot of silt that sits on the bottom of the jars. if you add this stuff, the water gets full of these tiny particles. i discard this, but you could use a coffee filter to remove it.

rick

 

[mooman]

Aspen, nice idea with the canning. I've been wanting to experiment with peat, but was looking for a way keep it simple, and avoid making peat tea every time I do a water change. I don't mind some prep if I get enough extract to last a couple months. Thanks for the idea. :biggrin: