A question from a fellow grower:
What would cause my hydrotin rocks in my hydroponic to turn white?
That is dried salt from your nutrients. All you need to do is: Get a bottle of any flushing agent sold by hydro store. I use Clearex by Botanicare. This product is designed to to draw out and dissolve salts in your plant and your medium between grows.
Some will say to bleach the hydroton, but I do not believe in using a slat to clean a salt. A commercial flushing agent is a great investment to have in the grow room. Peace.lw
An update from the fellow grower:
Thanks,will it hurt the plants? And do I need to do that now or before I use them again?
If you are talking about on the top of your hydroton in a current grow, then certainly do not use bleach! LOL This is salt and mineral build up from your nutrients and your water. It is very similar to lime buildup in your shower, sink, bathtub and toilet, etc. especially if you have hard water. This will happen more if you are using hard tap water in your hydro reservoir and is one of the reasons most hydro growers prefer to use r/o filtered water. In general, most of the time this will not harm your plants, however it could lead to nutrient imbalances in extreme cases – as it is representative of excessive nutrients or minerals in your hydroponic system’s water, also it sometimes is partially caused by a ph imbalance and hard water does tend to be a little on the alkali side of things. If you are in the middle to nearing the end of a grow – this may be normal – and as long as you have been changing out your nutrient water with a complete replacement of a fresh mix every couple to a few weeks, or more often in smaller reservoirs, you shouldn’t have a problem. Most of this will go away with a normal wash of your hydroton between uses, even when washing with plain old water. Using a commercial “flusher” is not a bad idea and many are safe to be used with a live plant and are often used in the final “finishing” week or two at the end of flowering, right before the harvest.
There is absolutely no reason you cannot clean your hydroton with a flush agent and re-use immediately. IN the process of cleaning you will rinse thoroughly; I thought was a given.
As far as whether or not to clean it in the middle of your grow; We need to know: What system are you using?
How far along are you in your grow?
In a bubbler I would not mess with it until harvest and cleaning, because the roots that are uptaking nutrients are under the net pot. If you are dripping, then it would be a matter of how far do you have to go. I’ll check back later for your response. Peace.
Of course I was answering this from the assumption you are using a Deep Water Culture system, as hydroton seems to be used most often in a net pot in a DWC bucket nowadays.
I get this question very frequently with new DWC growers that do not have the top of their hydroton covered by anything; asking about the white powdery or salty looking stuff that appears on the top, and I kinda assumed that is where the questioner’s mind was, lol.
Any growing medium can show “nutrient and mineral salt” build up or “crusting” on it’s surface. Again this can be a symptom of hard water and or excessive nutrient build up. It could be a very important sign to cut back on your nutrients. But if this was the case, you should probably have seen other warning signs already, like nutrient burn on the leaves. It can also be harmless for the most part, especially for your average short one season grow where you are just going to dispose of the medium after harvest. Especially in a lot of “soil-less” mediums you will almost always get just a little “crusting” at the surface or edges where water will evaporate from the medium leaving the nutrient salts behind. This is harmless and normal. Some people use “panda film” or mylar cut to shape to cover the medium while still allowing for airflow, this can reduce “crusting” on the surface and may even allow for more root area as the roots will be able to grow closer to the top surface of the medium having the light at the surface greatly reduced or blocked out.
For a long term grow, like maintaining a mother, you certainly should be flushing periodically to keep the plant healthy.
At the end of a Hydroton grow, as you can shake and break the hydroton loose from the root ball, and where you can rinse the hydroton thoroughly and reuse it, I was just mentioning that most of the white crusting would be washed away without the need for adding anything to “flush” it – if one is being very budget conscious. Especially if washing with r/o water, as r/o water is virtually salt and mineral free. And hydrogen peroxide can be used instead of bleach to sterilize it for those that are worried about some chlorine salts being left behind. Pharmacy/drug store – off the shelf – hydrogen peroxide can work, but that can be expensive because you’d have to use a whole lot of it, as that stuff isn’t very strong. You can buy agricultural hydrogen peroxide, that is much more concentrated, at some garden supply stores and you can certainly find it at specialty grow stores and online. This what most would recommend over the off the shelf stuff from a pharmacy/local drug store.
So; Back to my point. Use a Flush agent. Remove the salts and move on! Hydroton can be used over and over. There is no reason to ever throw away hydroton.
Lol; back to my point, a flush agent is not always needed.
I don’t think anyone is recommending throwing away your hydroton, some other hydroponic mediums are also reusable if you want to go to the trouble. But most throw away coco and perlite mixes as that stuff is a pain to comb or sift out your old root ball/system and it is so cheap to just replace. At the very end of a grow after you are already removing a mostly dead root ball from your hydroton – you don’t necessarily need to use a flushing agent. For the most part plain water will do fine to wash off your balls, lol, that is all I was saying.
Peace Latewood,
McG
do you have to flush with fox 
farms soil