Mold in hydroponics.

I've been growing in soil for a few years now and I wanted to try hydroponics. I have a pretty basic setup and this was honestly just my first attempt to see how it would go. I have a large water reserve with a pond pump circulating the water constantly up to the second container where the plants are. I have no temp. control of the water honestly and I know that is very important but once again I just wanted to see what would happen... I had a few plants in small containers with clay pebbles and the pebbles started growing while mold. Pretty much every article I read said I had to just get rid of the plants and bleach everything. I got rid of the pebbles and the plants in the pebbles but I had one plant in lava rocks. I wanted to see if maybe the lava rocks would hold up and not get mold like the others but it looks like the mold is hitting the roots on the last remaining plant so I imagine I'll have to toss the last plant and really bleach everything.
Does anyone have any suggestion/comments about this problem? Maybe some more simple fixes...
And this setup is inside a room that can get pretty humid and I also read that having the roots a certain distance from the water can affect mold growing.
So I know those two things along with no temp. control of the water can cause the mold to grow. I'm just wondering if anyone has any simple solutions that are not too costly.

I had a white build up on my pebbles & stem that eventually killed my plant......I was told to cover the pebbles with foil....once I did I had no problems. It was said to be a salt build up, but may very well work for you. Good luck

Thanks for the advice I appreciate it. From what I've read though it honestly sounds like it could be the temp. of the water, how low the plant is in the water and/or the humidity in the room. It could be one of those or a combination of all three maybe... I forgot to mention also that I have some small fish in the upper container too with the plants.

you can buy little heater wands to keep the temp up when it's cold, and just use frozen bottles of water a couple times a day if it get's really hot.
you should have no problem keeping a covered resevoir right around 60-65 degrees F

That is from light exposure, cover it.

My problem is keeping the water cool and the guy at my local store actually suggested the frozen water bottle idea too so I might try that. What growing mediums do you guys like to use by the way? And should I cover it up with foil like jojaxx suggested?

This site I found was pretty useful too and has a pretty good amount of basic stuff. Gave me some good ideas.
http://www.hydroponics-simplified.com/

The guy at your local store is an idiot. That is from light leak not water temp. They are two completely different looking problems and that is from light

I didn't say the guy at the store told me to use the bottles for the mold. He just told me to use the bottles to help control the water temp. Don't be so quick to pounce on something someone says wrong either man. I'm just looking for some friendly help.

i bet if you got a little airflow pointed down at the rocks it would prevent the mold

one of molds biggest enemies is fresh air

I gave you very friendly and accurate help based on lots of experience and thousands of harvested plants but you chose to insist its temp. Don't be so fast to believe the guy trying to take your money to feed his kids.

what nizza said, and make sure you are keeping everything clean both in between grows and every time you change your water.
clean clean clean.

Are those rock left over from a previous grow, did you clean them before using them again?

superstoner, can you tell us a little more about the light and why it would create mold.
im noticing you have a tendency to bark out orders because you have experience instead of explaining yourself.
it comes off angry.. try to more be patient. we want info, not orders.

Superstoner1 isnt wrong, Combine moisture with an energy source (light) and you have a breeding ground for mold. Throw some aluminum foil or a few plastic plates with slits in them over the medium to stop the mold from growing. As far as temperature of the reservoir goes have you considered simply using a larger reservoir? With enough capacity in your res you would be able to adjust the nutrient level to a point that the pump isnt over heating the system. Cost shouldnt be an issue since your setup has a remote reservoir almost any large container/tub/barrel would work. If you have a larger volume of water/nutes than you should be able to easily regulate the temperatures by adjusting the level. Once you know how many gallons it takes to keep the system at target temperatures you would be set.

If you are thinking about a re-do you may want to try something like this DIY hydroponics system. Looks like it would cost $40-$50 for the system plus the cost of a pump. Im guessing it could be running for under $100 if you were frugal about it. Anyways this setup might be a good way to try hydro on the cheap. I was thinking about giving it a try but ended up putting out the cash for a rail system as I am a legal mmj patient and can grow 15 plants so i needed the additional space. This setup is meant for growing huge plants and would only have room for maybe 6 smaller plants. Heres the link if you want to check it out. http://www.evolutiongrowled.com/diy-homemade-hydroponics-dwc-current-guide-plans.html

I do want to build a DIY hydroponic installment (or whatever the name is ,my english suck a bit sorry.) and from what i have found online ,everybody says that you must not let the sunlight pass through your root container...So dont use transparent material , or cover it with a dark foil.
By the way i found the most interesting information on DIY hydroponics . I will search for the link i have bookmarked and i will repost soon

Here it is

http://www.instructables.com/id/DIY-Hydroponics/

I have the fan in the room on almost 24/7 now so hopefully more air flow will help. I also got rid of the last plant sadly but I'm starting fresh with just one plant for awhile to make sure I have the problems figured out. But I cleaned all the containers and pipes out, cleaned the new clay pebbles I bought and sterilized everything. And my uncle also found a quick fix to the mold problem I was having just by adding a tablespoon of hydrogen peroxide per every 3 gallons of water I believe and it apparently helps kill the mold but doesn't harm the plants. Thanks to everyone that has been giving advice though I appreciate it. It's my first attempt at hydroponics so just learning the ropes like I did with soil at one point.

It;s probably more like calcium deposits on the rock from using a town or city water supply.

okay breathe and do this. any kind of h2o2 peroxide. if 3% use 50/50 with water and spray on the rocks. will kill the mold on rocks and then you are okay. then take and dilute that with same amount of water. spray leaves and poor the rest in res. then cover the rocks with mylar or anything that will block out the light. if at anytime you get mld even on your buds in bloom use this method to kill the mild and it wont hurt your plant or change the taste. i would buy a qaurt of 35% food grade add 1/2 oz to gallon of water and add to your res. do this 3 times a week and you will never have mold again ever. even if you dont cover the rocks. and your roots will love it.

You guys keep saying add things to the grow that just aren't needed. Simply covering the the area around the stalk with anything that will block the light will stop and prevent any further growth of the mold. Its the light.