Local (tap) water quality and its contents for DWC

Prismo

Member
*EDIT*: I've just discovered that there is a sub-forum for DWC. Could a moderator move the thread there if possible? Sorry, my bad, wasn't paying attention.

Sup.

First off, sorry for any bad grammar and such. English is not my native language, sadly.
And don't be scared off by the fact that I'm new here. It's because I don't like my "local" forum, they didn't offer any quality help on this one and several other topics.

Ok, so this is obviously a bit of a complicated topic because the contents of tap water are very variable around the globe. Right now, I don't have the possibility of using RO water, but this could change in the future, since I don't dislike the idea of having total control of your water supply.
Anyway, I have an excerpt of my tap waters analysis from July 2016 as its freely available. I'll be using metric values since I'm european and also because I'm way too lazy to convert those values, sorry. Translating the names of the chemicals is already some work, hehe.

I'll be using GHEs Flora Trio and Botanicares Hydroguard. Also, I have not yet received my PPM/EC-Meter but I will do so in the next few days, so I can test some values myself. I will post them here.

My questions to you guys are:
1. Are there contents in my tap water that could be harmful if used as is?
2. Is the amount of essential things like calcium and magnesium enough or should I consider using Cal-Mag? And if so, in which quantities?
3. Will I need some other supplements? And if yes, which?

Hardness: Soft
pH: 7,94
EC (at 25°C): 388 μS/cm

The water is treated by the provider with substances that remove iron and manganese.
  1. Total hardness: 1,45 mmol/l
  2. Calcium: 49 mg/l
  3. Magnesium: 5,6 mg/l
  4. Phosphorous: < 0,004 mg/l
  5. Potassium: 4,4 mg/l
Chemical parameters (in mg/l)
  1. Aluminium: < 0,001
  2. Ammonium: < 0,04
  3. Antimony: < 0,001
  4. Arsenic: < 0,001
  5. Boron: 0,03
  6. Bromate: < 0,005
  7. Cadmium: 0,0002
  8. Chloride: 34
  9. Chromium: 0,0004
  10. Copper: 0,0090
  11. Cyanide: < 0,005
  12. Fluoride: < 0,1
  13. Iron: 0,003
  14. Lead: < 0,001
  15. Manganese: < 0,0002
  16. Mercury: 0,0001
  17. Nickel: < 0,0004
  18. Nitrate: < 2,0
  19. Nitrite: < 0,007
  20. Selenium: 0,001
  21. Sodium: 18
  22. Sulfate: 67
  23. Uranium: < 0,001


Hope you guys will be able to help me out here. This will be my first DWC by the way (and I'm generally also still somewhat of an amateur) and I'll be using an additional pump to move water from the bottom to the net pot ("Bubbleponics") to save me some time in the first few weeks.

Peace
 
Last edited:

rkymtnman

Well-Known Member
EC (at 25°C): 388 μS/cm
that is pretty high. my well is 260 most of the year.

as it's your first dwc, i'd still recommend RO or distilled water until you get used to growing in dwc. i've done it for years and still buy RO water at walmart weekly. 37 cents a gallon
 

Prismo

Member
Yeah, I figured that it would be a bit high, considering all the stuff I've already read and watched.

I've received my pen by the way. It about confirmed the values from the analysis, I've got almost the exact same numbers.

I was thinking about buying RO/distilled water, but I'm not sure if I can get it that cheap locally. Not sure if this is as widely available where I live for a price I can afford, which isn't much right now, sadly. I will investigate if I can get the needed amounts for a good price.

If I'd be using RO/distilled water, what additional nutrients besides Cal-Mag would you recommend?

Peace
 

rkymtnman

Well-Known Member
I was thinking about buying RO/distilled water, but I'm not sure if I can get it that cheap locally.
if you think you will continue growing dwc, an at home RO unit might not be a bad investment if getting it locally is hard. but then you have to replace all your filters which can be costly

like i said, i use RO and have been using GH maxibloom powder 2.5 grams/gallon. EC is about 0.6 that's all i use. no cal/mg although having a bottle on hand is always good since those are 2 common deficiencies.
 

Prismo

Member
I think that I will most definitely keep using DWC, even though I haven't even started yet. I don't know a lot about other hydroponic methods but this one was the method that seemed most appealing to me. I will definitely keep using hydro setups though. I like the possibility of complete control and quick intervention if problems occur. I failed miserably with soil and I still don't know what the (major) problem was, but at this point, I don't even want to know. I've constantly had high temps and very dry air, both of which problems should be solved now with a different method of getting fresh air... but if it was indeed because of my tap water, I'd rather be on the safe side with that, that's why I've asked here for help.

Problem is, I would immediately get a decent RO setup, but I'm just really god damn tight on money right now and this won't change for some time. I only have enough to get started with it using the equipment I already have and the stuff I needed to add.

Peace
 

rkymtnman

Well-Known Member
but I'm just really god damn tight on money right now and this won't change for some time.
i'll give you something to try. hempy buckets. 5 gal bucket with 1 7/16" hole drilled 2" up from the bottom as a drain. i use 3:1 perlite to vermiculite. it's the simplest form of hydro. give one a shot using your tap water and see how it works for you. give you time to save up some money and also get some practice grwoing in hydro

hand water once a day or two days depending how big the plant is. can't overwater it either.
 

rkymtnman

Well-Known Member
or give dwc a shot with your tap water. they do make a hard water version of GH flora micro.

i just like RO water because it eliminates your water as a potential problem.
 

Prismo

Member
i'll give you something to try. hempy buckets. 5 gal bucket with 1 7/16" hole drilled 2" up from the bottom as a drain. i use 3:1 perlite to vermiculite. it's the simplest form of hydro. give one a shot using your tap water and see how it works for you. give you time to save up some money and also get some practice grwoing in hydro

hand water once a day or two days depending how big the plant is. can't overwater it either.
I really appreciate the helpful advice, but I'm not only short on money, but also short on time. Sadly, I don't have the time for different test runs. I'll have to start soon and it needs to be the one that I have planned, sorry. Can't say anything about details, but it is as it is.

or give dwc a shot with your tap water. they do make a hard water version of GH flora micro.

i just like RO water because it eliminates your water as a potential problem.
Well, I've already purchased the GH nutrients, but my water isn't that hard really. The city I live in has 4 separate zones where 2 zones are provided with very soft water and 1 zone with hard water; my zone is provided with water that has a bit more hardness than those 2 other zones, but they still call it soft, although I would say it's more like in between soft and medium according to the analysis and my readings. I don't think I would have to use the hard water nutrients for this.

I can see why you and others like RO water and I would really love to use it, too. So far I've found out that I can get distilled water (didn't find RO so far) for about 4-6 times as much as you're paying... not really a happy sight... especially not for my wallet.
 

rkymtnman

Well-Known Member
I really appreciate the helpful advice, but I'm not only short on money, but also short on time. Sadly, I don't have the time for different test runs. I'll have to start soon and it needs to be the one that I have planned, sorry. Can't say anything about details, but it is as it is.



Well, I've already purchased the GH nutrients, but my water isn't that hard really. The city I live in has 4 separate zones where 2 zones are provided with very soft water and 1 zone with hard water; my zone is provided with water that has a bit more hardness than those 2 other zones, but they still call it soft, although I would say it's more like in between soft and medium according to the analysis and my readings. I don't think I would have to use the hard water nutrients for this.

I can see why you and others like RO water and I would really love to use it, too. So far I've found out that I can get distilled water (didn't find RO so far) for about 4-6 times as much as you're paying... not really a happy sight... especially not for my wallet.
well, give it a go then! the GH feed chart for recirculating is a bit strong. start off at about a 1/4 of what they say and go for it. definitely use the hydroguard.
good luck! dwc is fun. the growth rate is amazing.
 

Prismo

Member
well, give it a go then! the GH feed chart for recirculating is a bit strong. start off at about a 1/4 of what they say and go for it. definitely use the hydroguard.
good luck! dwc is fun. the growth rate is amazing.
Yeah, I've found a good (I think) chart for DWC. It recommends low amounts, too, to start off with and see how the plant reacts, and then adjust depending on how it reacts. Good thing I've spent some bucks on getting the Hydroguard from the US, was definitely a major part of the investment.

By the way, I've found some rather cheap osmosis equipment on amazon for about 50€ that has 4 and a half stars out of 104 reviews. People say that it got their water down to an EC of about 10. What do you think about those? Reasonable if you're short on money? Seems to last a long time, too, with the right maintenance.
 

rkymtnman

Well-Known Member
By the way, I've found some rather cheap osmosis equipment on amazon for about 50€ that has 4 and a half stars out of 104 reviews. People say that it got their water down to an EC of about 10. What do you think about those? Reasonable if you're short on money? Seems to last a long time, too, with the right maintenance.
that's not a bad price.

you can always mix your tap and the RO which will lower the EC too. but still give you some Cal and Mg too. win/win.
 

Prismo

Member
that's not a bad price.

you can always mix your tap and the RO which will lower the EC too. but still give you some Cal and Mg too. win/win.
Good idea, mate. Should make it affordable.
And I'll look into that cheap osmosis equipment a bit more.

Thanks for your help so far.

Peace
 

rkymtnman

Well-Known Member
Good idea, mate. Should make it affordable.
And I'll look into that cheap osmosis equipment a bit more.

Thanks for your help so far.

Peace
no worries. anytime.
2 things I learned about DWC: keep your ppm/EC low to avoid overfeeding (watch out for burnt leaf tips) and keep root rot away (hydroguard or something similar).

have fun! start a journal when you get up and running and you''ll get plenty of help (some good and some bad)
 

Budley Doright

Well-Known Member
Heed the advice to get hydroguard if your not able to chill your water or it'll be a struggle. Also I have hard water and found that using vitanimo stopped leaf blotching and really helped the girls, just my experience but well worth the money and lasts a long time.
 

Prismo

Member
Heed the advice to get hydroguard if your not able to chill your water or it'll be a struggle. Also I have hard water and found that using vitanimo stopped leaf blotching and really helped the girls, just my experience but well worth the money and lasts a long time.
Thanks, I have already purchased the Hydroguard a few weeks ago. From the standpoint of experience, what method seems to be easier/more effective: Beneficial bacteria or no bacteria at all?

Also, I hope water temperature won't be a problem, but I'll have to see how it goes first. I haven't found anything for "Vitanimo", maybe you did a typo there? I'm pretty interested, since my water isn't quite "hard", but has still a lot of ppm I guess (~180-190).

Also, if using RO water, which nutrients do I absolutely need besides the base (FloraTrio) if any, and which nutrients can enhance flavor/increase yield if possible?

Peace
 

70's natureboy

Well-Known Member
I always heard soft water and sodium were bad for plants. I never tried it though. Make sure to let us know how it works out.
 

Prismo

Member
I always heard soft water and sodium were bad for plants. I never tried it though. Make sure to let us know how it works out.
Luckily, my water doesn't have that much sodium (18 mg/l) compared to what I heard from other people. So far, I think this number seems to be "not too high" but would be better off diluting my water down or just using RO. I think I'll get RO equipment and then just dilute my tap water down with a 50/50 ratio. Should net me a ppm of about 90-100. If deficiencies occur, I have some Cal-Mag ready.
I don't think I'm capable of handling only using RO water yet, without any practical DWC experience. I also lack some nutrients that I would probably need for that.

I think I'll be doing a grow journal, since I have a pretty good webcam which will be placed in the grow room. Once I have started the journal, I'll be linking it here for anyone of you that is interested.
 

Ryry94

Well-Known Member
Also, if using RO water, which nutrients do I absolutely need besides the base (FloraTrio) if any, and which nutrients can enhance flavor/increase yield if possible?

Peace
I run DWC with the the GH Trio, Hydroguard, floraliciuos plus, and liquid Koolbloom during flower only. You don't "need" anything beyond the trio, but the additives seem to boost my yield. And cal mag as needed
 
Top