Article 4-3 Cloudy Reservoir

Greetings and congratulations on a truly dedicated magazine and information base. Keep it up!
My question is why does my nutrient solution look cloudy and other times clear? It sometimes clears in a day or two, but not always. I employ a small ebb and flow and use DNF and sm-90. Should I add the sm-90 a few hours after the nutes. Water is 8 to 9 pH out of the tap, so I add some pH down before adding nutes and sm-90. I retest and adjust after to 5.8-6.2 pH. Res is aerated and circulated by a power head on the bottom. Any tips would be greatly appreciated, Cloudy.


Thanks for the inquiry and kind words. If you could specify the following details I could give you a more accurate diagnosis:

  1. what you use for pH control,
  2. type of growing medium,
  3. a water analysis,
  4. if the cloudiness is throughout the solution or on the surface (to determine this, temporarily shut off the power head). If the cloudiness you describe is only present on the surface of the nutrient solution, I suspect that the organic oils contained in the SM-90 are binding with growing medium particulate (I am speculating that you are growing in rockwool) and floating on the surface. If the cloudiness is throughout the solution I suspect that you have Hardwater as pH values of eight or nine are characteristic.

However, water processing boards may be adding chloromide to the water in your area, which can also elevate pH levels. If the problem is from your water try the following, in order:

  1. aerate the water for 24 hrs,
  2. run the water through an activated charcoal filter or preferably a reverse osmosis unit,
  3. ozonate the water and let stand for a brief period prior to mixing your nutrients.

If you like, please please forward some of the above details if the diagnosis given seems out of whack.
Cheers, Erik B


Thank you for your response and the diagnosis.

  1. Use Phosphoric Acid to lower pH number.
  2. 1″ rw cubes in hydrocorns; geolite
  3. Am looking for an accurate analysis, any suggestions where I can get one.
  4. The cloudiness occurs both as you describe. The ‘slick’ goes away, but the throughout cloud does not. Should I be aiming for a clear solution? Where would one purchase a reverse osmosis filter or even the charcoal filter you describe? Does the filter reduce TDS or other harmful additives? My water is municipally supplied and is 8-9.5 right out of the tap. The chloromide is a molecule of chlorine? Do you know its make-up (ClO_4 or 3, etc)? Thanking you for your kindness.

Nice to hear from you again. Ask your municipal water supply to provide you with an analysis, typically for a small fee. The high pH of your water is likely due to a high degree of “hardness”. The cloudiness you describe can be referred to as “turbidity”, a term used to describe suspended solids in the water. In your case these suspended solids are likely mineral matter. A reverse osmosis filter would greatly reduce the TDS of your water before you mix your nutrients and would certainly lessen the degree of turbidity. Micro filters are intended for removing suspended particles and some bacteria in drinking water. Activated charcoal filters will remove some chemicals and heavy metals, but should be used in conjunction with a particulate filter to improve the clarity. All filtration systems will require some level of maintenance to operate effectively. Ask your hydroponic retailer or a residential water purification equipment supplier about your options. Chloramide (H2NCl) is found in the form of monochloromine when the water has a pH of eight or greater. At lower levels dichloromine and trichloromine are formed. Chloramides eventually break down into chlorine and ammonia. Ozonating the water may this can help combat the wet soil often experienced early in the season.

For containerized plants, add about 15ml (one tablespoon) per 3.785 L (one US gallon) of growing medium. So, one tablespoon per gallon size of pot: three gallon pot requires three tablespoons. It is best applied when transplanting to a larger sized container. So use once from clone to grow, and once from grow to bloom. After plants have initiated flowering, you should refrain from transplanting, as results will suffer from the shock induced. Do not mix directly with dry, granular fertilizers with phosphates or sulfates, as they may react with the calcium peroxygen.
Sincerely, Erik Biksa

Have you heard of the combination hydroponics Aeroponic systems? If you have any info on these I would like to hear about them, (where to get one, maybe plans to build one, prices etc). Thank you.

Yes, The type of systems you mention are used by hobby growers, and to some extent commercial growers. The systems can be purchased complete, for different types se the ads in Max Yield or other publications. If you have little experience with this type of system I recommend purchasing a complete unit before updating the design to construct your own. Components to construct your own are available from retail hydroponic stores. Most Aeroponic systems are either constructed from tubes, troughs with lids, or from modified ebb and flow tables. For nutrient injection, the nutrient solution is delivered under great pressure via small holes, microjets, spray nozzles, and micro sprinklers. You do not need to buy specialty sprayers.

The basic principle is that if the nutrient solution is delivered under high pressure via tiny holes in a line and sprayed against the wall of the tube, trough, or table the spray will diffuse into many tiny droplets creating a fine mist for maximum absorption of oxygen and nutrients. Also, by avoiding spray nozzles, etc. clogs are less likely to occur, although adequate filtration is a must. For some diagrams and more details please visit my website at:
Sincerely, Erik Biksa

We have a container garden of about 40 plants of different variety flowers, mostly perennials, two trees-a lilac and a small maple, also in pots. Last year we watered with a hose, sprinkling the leaves as well as watering the dirt and roots. We seemed to have a lush garden.

This year, because of water conservation, we are using a watering can to water. The garden seems less lush, the flowers are growing but are not profuse. We do feed regularly.

Could the lack of the leaves ever getting any water be the reason for such a weak looking growth on all the plants. The sun seems also to burn the plant leaves faster. What are we doing wrong and what can we do better. Thank you.

Sounds like the might be time to repot the specimens into larger containers. Also, when conserving water, growers may experience some salt build up in the root zone, as excess salts are not being leeched away. The results are often the symptoms you describe. Make sure that a good volume of water (i.e >15%) of the container volume is allowed to run off.

Also, if using slow release fertilizers containing urea, the chances of toxicity also increase. Be sure to check the soil pH. Adding plant available silicate to the irrigation water will help reduce plant transpiration, thus conserving moisture and increasing resistance to insects and disease.

In my opinion, the only reason you may need to sprinkle the leaves with water is to clear dust away from the stomata (tiny holes in the plant’s leaves for gas exchange). However, you can count on an occasional rainfall to do this for you. Hydroponic plants make much more efficient use of water and nutrients and also offer a higher level of control.

Cheers, and thanks for doing your part to conserve our water.
Erik Biksa

Can you give me some insight and tips on watering. I just started using five vacroc cubes in a top feed system. Is there a rule of thumb, or is it something you just have to trial and error?

Any advice you have on this subject would be greatly appreciated. Also is there any brand of nutrients you recommend over the rest. I’m currently using Ionic. Thank you for your time and wisdom.

I don’t think it would be appropriate of me to recommend one brand of fertilizer over another to you. What I will say is that I personally prefer having a greater degree of flexibility with a nutrient program. Always make sure that any fertilizers to be used hydroponically contain all the necessary elements for plant growth: Nitrogen, Phosphorous, Potassium, Calcium, Magnesium, Iron, Zinc, Manganese, Molybdenum, Boron, Copper, and in some instances silicate (for resistance to wilt and disease), cobalt and nickel (for plant B6 and B12 synthesis-stress relief). If using high quality water, especially for use with rockwool, make sure that there are adequate levels of calcium.

For irrigation, use lower nutrient EC or TDS levels in hot, sunny weather and higher values in winter months (lower light, shorter days). If draining to waste allow at least 15% run-off with each irrigation to leech away excess salts and prevent the root zone from becoming toxic. You don’t want to keep the cubes soaking wet, but you must not allow them to dry out as rewetting can be difficult with rockwool and pH values tend to climb higher than considered optimal. In rockwool, I maintain a pH of 5.5 in the nutrient solution which typically results in a pH of 6.3 in the root zone. You will not likely need to irrigate during the dark cycle. To simplify things try irrigating for 30 seconds every 15 minutes during the light cycle. Maintain this as constant, but install a flow control valve in the mainline or use emitters rated for different volumes to vary the amount of water supplied as required through out different growth stages.

It would seem that when plants are smaller they would require less water. In a way, this is true, but there is less foliage covering the media and increased evapotranspiration from the exposed media can result in significant water consumption (much to the surprise of many growers).

Keep at it, and you will find what works best for your situation.
Regards, Erik Biksa