Tap Water-Distilled Water-Filtered Water

[RenettaHogan]

I was wondering if everyone out there uses distilled water when setting up their hydroponics systems? If you use tap or filtered water, what type of changes need to be made when it comes to TDS. I checked my tap water and the TDS level is quite high already. Do I add the TDS nutrient levels to the tap water TDS to get accurate levels of nutrient? For example, if the tap water TDS is 2010, do I add 1700 (nutrient) to that number to get the correct levels of nutrient for the plants? Also, which would be better tap or filtered? I don't always have access to distilled water and am looking for a more user friendly way to help keep my system running efficiently and effectively. I'm quite new at this and want to get it all down correctly before taking it into my classroom. I'd appreciate any info on the matter.

[GpsFrontier]

Originally Posted by RenettaHogan

I was wondering if everyone out there uses distilled water when setting up their hydroponics systems? If you use tap or filtered water, what type of changes need to be made when it comes to TDS. I checked my tap water and the TDS level is quite high already. Do I add the TDS nutrient levels to the tap water TDS to get accurate levels of nutrient? For example, if the tap water TDS is 2010, do I add 1700 (nutrient) to that number to get the correct levels of nutrient for the plants? Also, which would be better tap or filtered? I don't always have access to distilled water and am looking for a more user friendly way to help keep my system running efficiently and effectively. I'm quite new at this and want to get it all down correctly before taking it into my classroom. I'd appreciate any info on the matter.

That is a good question. As I understand it, there are some trace elements that are found in water that are necessary for plant growth and health that are not in the hydroponic nutrients because they are already found in the water, so even though distilled is the most pure I don't think it is the best choice. As for tap water it really depends on where you live and where your tap water comes from. Do you live in the mountains and does your water come from a well in those mountains or do you live in a large city and the water comes from the main city line? The water purity is different depending on many factors. I live in a small town and the city water here is mainly from the lake here in Lake Havasu, but it is very hard water due to all the minerals in the ground especially Iron. We have a water softener but I think the water from the reverse osmosis is the best choice for me. I don't have a ppm,tds,ec meter but just change the solution more often as well as keep up with the pH level. I don't know what nutrients you are using but I think if you e-mail General Hydroponics tech support at: tech@genhydro.com They would be able to give you the best and most accurate answer to your questions. I don't know about weekends but they usualy get back to you within 24 hr.

[HydroACR]

I agree, distilled, pure water is probably no the best, if your buying water because your worried about your tap water, I would go with some kind of natural spring water....

[Toleman]

I use rain water with good results. You need some ph up though as its about 5.5.

Ec of my tap water 0.8 (8cf)
Ec of rain water - less than 0.1 ec (1cf)

[Luches]

Originally Posted by GpsFrontier

That is a good question. As I understand it, there are some trace elements that are found in water that are necessary for plant growth and health that are not in the hydroponic nutrients because they are already found in the water, so even though distilled is the most pure I don't think it is the best choice.

Actually you should have a analyses of your Tap Water to exactly know its content. I do not know about the US or other countries, but in many EU countries, you can ask a water analyses of your Tapp water for free from the Government (office in charge).There may be trace elements but in most cases they are of no concern except Chloride. Most important to consider is the content of Mg, Ca and Iron of your tap water.

In Germany there are some mono-mixes and dry nutrients that come without any calcium, others have low Mg-content, simply assuming that most Tap water in the country is soft and contains high calcium and Magnesium - hence the product explicitly says SOFT. As the Us is a huge country with multiple geological conditions, I doubt such a manufacturers strategy. Though, - dry and mono-mixes may come without or very little calcium due to some manufacturing issues. In case you have got hard water or use rain water, be aware of the possibility of a lack of calcium in case you use calcium-free nutrients, and perhaps lack Mg or in some cases even Fe as well, if Fe EDTA is added to sparingly! Especially when growing tomatoes and other night shade with big crop size or heavy yield.

Other trace elements, like Mn, Cu, B, Mo etc - may as well be part of any tap, or other water source (except rain or distilled and/or treated water), but normally not sufficiently. They should always be part of (covered by) the nutrient. Well, in some rare cases the general role doesn't apply and Boron may reach nearly toxic levels, or other elements may be contained in unusual amounts. Minor trace elements, like Si, Ni even Cobalt are not always, but sometimes supposed to be contained (as contaminants) in raw materials used to manufacture nutrients - but not supposed to be part of Tap water. Newer research tells that they are not vital for growth, but may have an impact of health and various immunitary functions.

In this domain there is actually not much room for guessing and speculation (no offense though, for any previous guess or suggestion). In fact it's a topic that is often underestimated in normal cases but in untypical cases even more vital and can be cause of serious imbalance!

Using distilled water is best if you have good knowledge of plant needs and know the exact content of your nutrient (respectively know how to add missing elements). In that case all single element should be provided by your nutrient. For instance it would be the best choice for people who make their own nutrients, but only if there is reasonable consumption or for testing purposes. In my case, total consumption of around 10 setups reaches up to 150-200 Liter a day in hot season. I don't see how I could provide that amount in distilled water. From a industrial level, it's obviously a no go.

[KevinL]

I use distilled water in my systems so far, but will be switching to rain water once I get a catchment system setup. Distilled water is PH Neutral in most cases.
I live in the boonies with well water that is very hard and you can't use softened water for hydro-systems.
When I had my NFT outside, I went through a LOT of water, and even at 69 cents a gallon bottle..it was spendy when it was all done and said.
The only problem I had with using distilled..and I don't think it would have been any better using filtered or tap...calcium definancies which cause bottom rot on tomatoes. It didn't affect the grap tomatoes, but the full size ones were awful.
And for anyone else that has that problem....I have ONE solution, One Word.....TUMS! If your doing tomatoes, Add a couple tums to your solution, it will make all the deference in the world.

[Luches]

The appropriate amount of calcium in a tomato formula is around 150 ppm and for leafy vegetables a bit higher or up to 180 ppm. In most cases, the calcium content in a nutrient solution for tomatoes isn't the real issue, but excessive vegetative growth (due to warm climate) in combination with immobility of calcium. The amount of calcium has to be sufficient, though!

Originally Posted by KevinL

And for anyone else that has that problem....I have ONE solution, One Word.....TUMS! If your doing tomatoes, Add a couple tums to your solution, it will make all the deference in the world.

I don't agree here, because TUMS mainly provide calcium carbonate:
CaCO3 is insoluble and inherent pH problems are to be expected! CaCO3 is NOT a component, that is used in any decent nutrient formula.

Best is to supply calcium with calcium nitrate (as part of the formula, because it provides N) supplemented by a small amount of calcium chloride. In case water already has high chloride content (some city water) calcium chloride has to be used even more sparingly or to be dropped.

[KevinL]

Excellent information Luches, thank you!

I have had friends use tums in their systems when bottom rot was a problem, and had success...maybe it's a fluke.

I will however take your more logical antidote and try that next time around.
but like I said, ..I usually do my Tomatoes in soils. 60 of them last year. (ok, it was a bit excessive..but I had a great success in germinating this year.)

[Luches]

Originally Posted by KevinL

I have had friends use tums in their systems when bottom rot was a problem, and had success...maybe it's a fluke.

It actually raises PH, and in some "rare" cases PH has been way too low anyway, it could indeed help. But as for providing calcium in a nutrient solution, I'd still rate it as a fluke. Unfortunately there is a lot of misconception in this field, that is actually a result of cherry picking (or call it purely circumstantial observation). In some cases personal observations of any kind may be very useful, in some others they are falsely applied as a general role for something else

PS: still be careful when using calcium nitrate, as it may provide unwanted nitrogen (and induce too high vegetative growth for tomato). Best is to include it in a formula or use a product that is based on calcium nitrate and providing sufficiently Ca.