how to deal with bad tap water in a DWC Hydro Setup (GHE Maxibloom)

I hope it is ok to post it here, wasnt sure if it s newbie or general?, feel free to put it where you want.
I am new here, Hello!

I have out of the Wall.

EC at 25 °C μS/cm 735
pH- 7,4
O2 mg/l - 9,0
total hardness °dH - 17,1
Carbonat hardness °dH - 9,4
Base capacity (KB 8,2) mmol/l - 0,27
Acid capatcity (KS 4,3) mmol/l - 3,4
hard water

Calcium mg/l - 108
Magnese mg/l - 8
Natrium mg/l 36
Iron mg/l 0,01
Mangan mg/l 0,02
Ammonium mg/l none

Chlorid mg/l 50
Cyanid mg/l none
Sulfat mg/l 145
Nitrat mg/l 1,0
Nitrit mg/l none
Fluorid mg/l 0,10
Bromat mg/l none

So thats not good, especially considered the amount of calcium in it.

Right now i use Hesi Cocos in Cocos which works ok so far, not great, but ok.
Later on i want to switch to GHE Maxibloom, like that its good for Hydro and it is nicely concectrated, less to carry arround.

Right now i think how to deal with the Water.

3 Options

1. take it as it is with Maxibloom and may go a little lower EC then normal, 0.2-0.3 maybe and let it go.

2. using a Waterfilter who changes a part of the calcium ions to magnesium ions, so EC would stay similar (may 0.1 lower) but there will be more magnese then inside and less calcium.
(there are several types of this filters, most change calcium to natrium, useless for us, but one type does it to magnese instead of natrium, this one i would test)

3. going for a RO osmose unit, there is no problem to afford one, more that i dont watn to have such a thing in my kichen somehow, ugly clunky, slow, pain to use
(i have no, RO Waterstation nearby, best would to carry it from homedepot, lots to carry, lots waste, not my favorite option).

Goal is to get some usable Water for ok to very ok results and get some stable water ph wise.

So far i can say the Tap Water is at least quite easy to PH down and relative easy to keep within the 5.5 to 6.5 range, probably
cause there is so much calcium in it that the GHE Phdown powder never runs out of buffer.


I would really welcome some thoughts of you guys, in best case someone dealt with a similar water, GHE Maxibloom and a DWC (probably going for a 9 Gallon DWC for one plant, later on).

The easiest way to gauge water is by ppm.

If it's over 150,,,,find another source.

RO - period.... So why does it have to be in the kitchen?

Set up a tank with a stop switch and use a high pressure RO pump! hell, you can get the pump and the switch as a kit on ebay for 1/2 the price of a pump at a grow shop!

http://www.ebay.com/itm/Reverse-Osm...554951?hash=item2c5caf5307:g:vzoAAOSw9mFWNS8o

You can use any size tank you want......Plastic (food grade) drums to tanks that are made for water storage....

55 gal tank filled in about 12 hrs...

thank you for the reply!

My EC is 0.735, so at 0.5 conversion it is ca. 370ppm, at a good 100mg CA and just 8mg MG.
I know this is bad

hmf, ok will dig into osmosis more.-)
I live in a regular flat, so i would need a Tap, have one in , tada, kitchen and bath
Could do some weired instalations in my kitchen if really needed, just dislike that somehow.
Also having a huge tank sitting in my kitchen isnt that nice.
So if i get away somohow else, i could imagine that this is my prefered choice.
Could get demineralized Water for relative cheap in containers, but have no idea if this is a good idea over the long run.

I would be ok filtering my water, that is easy to handle, so at least removing some calcium and exchange to magnese is doable.
Just say if i get it dialed in,with my (may just ion exchanged) tap, i would be a happy camper.

I target a max 10 Gallon container for the DWC, due to my lack in experience in this it is hard for me to judge roughly the needed amount of Water.

question to the GHE users, you use 100% Ro water for your mix, or do you ad some tap water too?

I've been using RO water for the past few years in my 4 x 5 gallon DWC. I fill a 65 gallon container weekly with a portable RO system without the mineral replacement filter. I use RAW cal/mag at each change and top off with excellent results. I just hook it to my kitchen sink and within 9 - 10 hours the container is full. Do you pay for the water at your flat? Please remember that the RO process wastes water at 2 or 3 gallons to 1. Mine is dialed in at 2/1 ratio. If you pay for water you might want to consider a gravity fed water purifier. There are some great filters out there. Good luck to ya!

I have basically the same tap water....

Ro unit is the least expensive most reliable but you have to add to make .4 ec

my tap water is ca. 2$ for 250 gallon, so wasting a bit there shouldnt be a big deal, like taking a bath once a week... cost wise.

There are indeed great RO units, one 2000l with 3l tank is 100$, not bad.
While i saw a very small (those usual prtable ones) with a 150GPD membrane for a similar price too.
Both should be usable, the smaller is 0,4l a minute the big one will be ca. 2l.
The price isnt really a concern there, more the installation, so aiming for the small protable 570l one (not really a plumber more for electronics).

You get me more n more going for osmose, right from the DWC start, really wanted a KISS DWC, as most a s possible.

The gravity feed ones will do just a ion exhcange as far i know, magnese calcium to natrium (not good , or?), it hardly lower the EC/PPM itslef, it is just a other salt
There are other brands then britta, like bwt magnesium+, they do the ion exchange from calcium to magnese, but they are seldon.
Think this is what the interessting water thread here in this section tells also.

But, i read often that people add calmag to GH Maxbloom.
I would have plenty of cal in water and with a special dirt cheap easy to use ion exhange filter i would have some of the calcium converted to magnese.
So idea was, why removing all the stuff when you add it later anyway?

Thanks Lemon King, thats a good hint, read this often that you mix it 50/50 (of course that depends a lot).
Which ferts are you using if i may ask?
I could may do also the overkill method then, doing the ion exchange for the tap and mix this with the RO Water.
While thats not Kiss at all anymore.

Really a bit unsure which way to go, i normally overdo, this time i wanted to try to reduce it to the needed things, not looking for the last ounce, more a steady going easy to care system.

The calcium in many municipal water supplies is in a large molecule form that plants have trouble taking up. So far better to remove with RO system and add back in more usable form.

but shouldnt the molecule size not the same as long it is in dissolved form?
of course it falls out easily, but before?

You almost convinced me doing the RO installation, i read up about the portable one now.
Plan a 50-50 mix, or whatever gives me EC 0.4 (read often 0.3 but well...), and a bit epsom salt was planned maybe so far.
Also have a very slight problem to get calmag, no local shop carries it, hm, should that tell me something?
Those 2 stores arent small, they have huge halls full of everything, but no calmag.
GH isnt as famous here it seems also, while i can get most of their line, all fine.
Could order online easily, but would like to have a local supply.

will go for a 150gpd reverse osmosis, decission made.
That could be usable for my needs.
Thanks guys, you convinced me that this is a good base.
I think i can do my ladys in coco which i have atm something good too, so.

Seems to me that you might want to try using the tap water first and see how it performs. I have been using MaxiBloom with tap water for years with zero problems, and I don't need cal-mag.

MickFoster said:

Seems to me that you might want to try using the tap water first and see how it performs. I have been using MaxiBloom with tap water for years with zero problems, and I don't need cal-mag.

Click to expand...

same we me, tap water & MaxiBloom but i do need Cal-Mag.... it all depending on your tap water, some need it, some don't

great, seems i choosed the right fertilizer, cause it seems to be widely used (important factor).

haha, was allready in to ordering a reverse osmosis, probably will simply do that and try.
That one will have a , therotically, 150 GPD filter, which should give me the wanted resluts in an hour waiting time.
In to figguring out if it fit directly in the shower, which would be halfway convenient.

At least i eliminated the waterfilter who does the cal to mg exchange.
Thats a variable too then and i am not experienced enough for this.

I have 108mg calcium in the water and 8mg magnesium, using it somehow tells me that epsom could be a good idea.
For the calcium, as i have no idea if the molecule size matters or differs, i would simply see first.
But accoridng the statements, it is really something to have an eye on and is unlike the boosters or similar maybe really important for me.

So RO, RO/Tap mix, or Tap only.

Trying the tap, was really a idea, still play with that option.

I use straight Tap right now on cocos, GH PH-, and Hesi Cocos.
Tbh it basically works, none dead, but i had better looking plants in the past, years ago.
Could be that some mag would be good there.
I think the best results i remember where on cocos with canna cocos and straight tap water.

I have no idea how the PH will behave from RO Water, as it have no PH, or it changes fast due to air contact or else, soakin every mineral.
One thing confuses me here.
Lucas Formula is based on RO Water only (makes sense,to make it comparable, cause it is used worldwide), but most recommend to harden the RO a bit (as above mentioned to EC 0.4, 200ppm).

i am just reading generall advices for hydro plants.
It is said a Plant needs 6 mg/l Calcium and 20mg/l magnesium min.
It can easily tolerate 100 mg/l C. and 30mg/l M.
If below 60mg Calcium and below 20mg magnesium each liter, add some by epsom and plaster.
Those are recomendations not specific for our plant but those are scientific results, a bit generalized from a thrustworthy source.

so my 108mg C could be "ok" my M is too low at 8mg.


But so far, osmose unit is ordered, so hard water is relative now for me
The 50/50 Ro tap mix looks quite tempting,as there is some mag. and calc. in the maxbloom allready.
In worst case some epsom should fix it then.

Bugeye said:

The calcium in many municipal water supplies is in a large molecule form that plants have trouble taking up. So far better to remove with RO system and add back in more usable form.

Click to expand...

This is exactly correct!

cobshopgrow said:

but shouldnt the molecule size not the same as long it is in dissolved form?
of course it falls out easily, but before?

You almost convinced me doing the RO installation, i read up about the portable one now.
Plan a 50-50 mix, or whatever gives me EC 0.4 (read often 0.3 but well...), and a bit epsom salt was planned maybe so far.
Also have a very slight problem to get calmag, no local shop carries it, hm, should that tell me something?
Those 2 stores arent small, they have huge halls full of everything, but no calmag.
GH isnt as famous here it seems also, while i can get most of their line, all fine.
Could order online easily, but would like to have a local supply.

Click to expand...

NO!

There are many forms of Ca. Some are better used by the plant and some would be a better buffer to the water (soil too for soil growers).

Look, The difference between running RO with nothing but the Ca/Mg you add to buffer the water and supply the plant and tap water that contains 350ppm of mineral content......Is like deluting your nutrients you use and thus your plant is not really taking up the best effective nutrient ratio!

The first harvest from RO and Ca/Mg from tap (well) had a very visible increase in bud size and density. Naturally this increased yield and even end quality....

I can not say strongly enough. If cost is no matter, and you want the best result. Go directly to RO!

you convinced me going for a RO, it is ordered allready and should be easy to install in my shower

So that wont be a the problem and i am sure my ladys in cocos will love it too.

but for the calcium moelcules i will read up more, at the the guys from the hydro club use the calcium form the water, they are mixing you a custom fertilizer also based on your water analysys.
I mean they use straight hydro, not soil where a molecule may dont have to be directly avaiable.

But in the end, getting some calcium sulfat is quite easy, biggest problem is i dint saw bags under 25kg (less then 20 bucks).

So i will go for RO.
Just unsure which mix, probably 50/50 as suggested above.
Will see what i need to add, at least i got a basic feeling for mg and c.
As far i understood you would use 100& RO and just add all from bottle.

In the end we get in to the teritorry where it need to be tested as all cooks seems to have a little different results.
I think the rule of thumb advice from the hydro society above regarding the water isnt so stupid and at least something to orientate.
Think if i read more there will come more together, one thing maybe, hydro society says, have 60mg Calcium in Water, 100 could be ok, while they say the plant need 9mg.
For Magnesium they say the plant need 20mg and you should have 30mg.
So they may take in to account that the form of calcium isnt that good avaiable, but good enough that a given ratio work.
Just theory so far, will dig in more.
But i will have the option going 100% and additives if wanted.

I read a bit.
Tap Water CaCO3 will become Ca(NO3)2 (what calmag have inside) after it got in contact with a acid (NCL in htat case).
So the acid in the fertilizers as also of course the ph down should hlep in making the CaCO3 avaiable to the plants.

Still looking for some calmag, calciumnitrate is hard to get it seems here.

from another Forum from User: justiceman

Calmag nutrients
*Botanicare calmag plus = Calcium nitrate, Magnesium nitrate
*General Organics calmag+ = Calcium carbonate, Magnesium carbonate, molasses
*Organicare Calplex, Organicare Huvega = Calcium carbonate, Magnesium sulfate(with other various trace minerals, and low molecular weight molecules)

Try here, https://www.amazon.com/Industries-C...1487031519&sr=8-16&keywords=npk+raw+nutrients

thats a alternative to GH Maxibloom as far i see, not bad.
Seems you like it and it is good.
Problem is it have to travel the pond, probably not worth it.

There seems to be really a law for calcium nitrate here, nope, not really to get.

There is a swiss brand called "chrystal top", they offer a similar fertilizer as maxibloom in powder form, they have a such a cal mag suplement in their line, avaiable.
But their Calmag suplement is simply seaweed based, same you give your dog or put in garden.
So their suplement is also only calcium cabonate, (from this carbonate a 30% roughly should be avaiable to a organism btw, i read.)
Best i can get is calcium sulfate, which is plaster. (which is indeed widely used in hydro and recommended as far i read).
Sulfates should be also easy to get for the plants as nitrates do, my 2 cent.

i am glad the forum is back.
thanks again for pointing me in the right directions.
Learned a lot during the downtime about what is in our water (or could be).
Most of my Calciumin the Tap is probably due to Calcium sulfate, cause there is quite some sulfate in it too, also the PH isnt so high and there is a limit how much carbonate can disolve.

Usin gthe Hydrobuddy software now, which i can really recommend to anyone who dont want to tap in the dark anymore.

In the future i will also only go for fertilizers who list all which is in, in percentages, otherwise you will never know.
At least for NPK and Ca and Mg Sulfur have rough ideas, while you can read till youre death about different recommended ratios, to know whats inside is a good start.

Having a RO unit installed now and can play with with my water values now, which is sweet.