RDWC problems.....Any advice welcome!

[Shackleton]

Hi everyone,

So I'm relatively new to the RDWC world, I decided to give it a try after many,many,many months of research thanks to the like of Heath's Deciple, Sqydro, Hannibal and a few others (sorry i've forgot a few names). Although I felt confident enough to take plunge I seem to have fell somewhat short.

Be it beginner's luck, my first attempt at RDWC yielded the best results and it's been pretty much down hill from there.

I'm currently using 4 oxy dripper tanks (3 for plants 1 for main res) each fed by a it's own maxi jet 1000 (3 in total), with two 40mm waste pipe returns from each bucket to main res. I'm using a chiller for the day time and a nute heater at night to keep water temps stable at 19-20C. The feed to each tank makes a waterfall to create DO and I have also created another waterfall in the main res using the return from the chiller. The plants were vegged in 15 litre trays made for the oxy tank with drippers until the roots hit the res. For those that don't know the oxy dripper (or brummie bubbler I think its known as) is basically a 90 tank, from which you use about 40-50 litres of water then sit the 15 litre tray on top, water line is sitting about an inch up from the bottom of the 15 litre tray. The medium in the tray is clay pebbles. The water is changed every week to keep things fresh.

The plants are critical kush from seed, currently in 5th week of veg. Each plant has its own 600w light, I know this is excessive but I will explain why soon. I keep a daily check on ph and ec levels, ph being 5.8 and ec is at 1.3 at the moment ( background ec of 0.5). The nutes I am using is canna aqua as it's made for medium hard water.

My first attempt was with normal bulbs in shades with 20ltr buckets and was a great success, and then with 50 ltr totes and with the current tanks with limited and no success. My first switch to the totes was kind of ok but struggled through veg, and the second attempt died 5 weeks into flower and which also struggled in veg. Why they died I have no idea, they just stopped drinking, packed up and wilted away. I used the exact same shedule as previous successful grows so to me it’s a mystery.

When I switched to the totes I also started using vertical lighting as I have seen so many good results. Whether my problems are associated with hanging bare bulbs or whether it is just coincidence I do not know. The bulbs are hung 8-10'' away from plants so no heat stress.

It seems as though I'm getting more and more problems when really I should be getting less and less. I always veg using 600w metal halide but my main problem is little or no growth, as I mentioned they are 5 weeks in veg and 2 are 16'' tall (about 1 1/2 feet tall) and the 3rd it around 20''. I have since gave them a 600w light each but none of them have grown for over a week now which is following the same pattern as when I moved to the 50 ltr totes. I check the roots daily and they too seem to stop growing whenever it suits them. Around 12 days a go I put a bulb back in a shade and placed it over the top of the smallest plant to gain some height, but to no avail.

I have been putting the stunted growth down the vertical bulbs as it coincided with the first time I encountered problems, but now I'm not so sure. I'm getting some older fan leaves that are yellowing with brown spots but the new growth (whenever the bastards do grow) is fine. This time round my ph is dropping whilst my ec is stable, this is a new problem and has never happened before as it normally rises steadily.

I have a 6'' outake fan and a 4'' intake, room temps are around 26-28c daytime and around 18-20c at night.

Humidty is about 20%, ive tried different humidifier's but they don't make a difference, I rekon to sort it properly I would need to pay £300-£400 for a professional humidifier.

So, to sum up;

3 Critical Kush feminized from seed
5th week of veg
4 tanks holding 40-50 litres each
MJ1000 to each bucket and chiller (4 in total)
2 40mm tank connectors per tank with 40mm waste pipe returns
Canna Aqua
E.C. 1.3 (background 0.5)
PH 5.8
Room temps 26-28c day, 18-20 night
Res temp 19-20c 24 hours a day
Waterfall in each tank for DO
Room size 3m x 2.5m
Vertical bulbs 600w

I'm sorry if i've confused anyone, I hope that's all the important info I know I will have missed something out. Any advice will be appreciated as I am almost resigned to going back to standing buckets and airstones.

Just to add, I spoke with a guy from a hyro store about all this today and recommended I put the water pumps on a 15 min on/off timer. He thinks there may be too much oxygen in the system and the plants don't like it. I'm not convinced about this as I've seen sytems run with more powerful pumps that recirculate faster, nevertheless I am going to give it a go and see what happens.

Thanks or taking the time to read this,

Ernest

[Bud Lightyear]

Hi and welcome to the forum, Hannibal is RDWC guru here....Im sure he will be along to point you in the right direction soon.

Regards BL

[Shackleton]

Thanks BL, appreciate it!

[Hannibal]

Just had a read through that, from first look I would say your suffering with light in the system. As the only thing I know, that will kill a plant stone died like that is algae. As you have moved the bulbs from horiontal to vert, you have exposed the system to light, where as before the canopy shaded it. Hope that helps bud.

Cheers BL.

[Shackleton]

Hi Hannibal, I've lost many hours and evenings reading your diaries and contributions to other threads. Thanks for your thoughts.

I have thought about algae, but as I couldn't really see anything wrong with roots I just dismissed it. I had covered the top of the tote with total blackout, just cut a slit for the stem, but now come to think of it on the 13mm pipe going into the water it was a bit slimey but I thought it was just salt build up. Am I right in thinking H2o2 with get rid of any algae, or would it break down on its own once light is blocked? Also, do you think light leak would contribute to the slow growth?

Thanks

[seanMcPot]

Not sure if this will help but if you want to add humidity to your room you could try a "fogger" (look for pond foggers on youtube)there only cheap as well

[Hannibal]

Its no trouble fella, we all help each other on here.

No algae is a difficult beast to spot some times, it can just be in the form of a clear snot, as you describe. But I would say its right TBH, and it could be in the root ball above the water. The change in light may have triggered it off. all that is needed is good covering and make sure no light get in.

From the minute you add you chorinated water, your on the stop watch against bacteria. Any change in the enviroment can start, change in what bacteria is produced. So in order to stop this, you have two options. sterilise the roots or treat them with benificial bacteria.

My choice as you allready know. TNC mycorrhydro.

[Shackleton]

Ahh of course.... The algae would be contributing to the ph drop I'm currently experiencing as well I bet....Damn it all seems so simple now

Yes I remember TNC...I'm not sure on the dosage though, do you think maybe the 450g will be the better option to buy as I'm changing the 160-180 litre system every week? I think I may flip to 12/12, soon is it safe to use throughout flower?

I think from now on I will keep a tub of this for the future, and make sure its it's put to good use!

[Shackleton]

Not sure if this will help but if you want to add humidity to your room you could try a "fogger" (look for pond foggers on youtube)there only cheap as well

Thanks seanmcpot, I'm going to have a look on youtube now! I don't think I can keep returning humidifiers back to the store because they don't work

[stealthgrow]

Ahh of course.... The algae would be contributing to the ph drop I'm currently experiencing as well I bet....Damn it all seems so simple now

Yes I remember TNC...I'm not sure on the dosage though, do you think maybe the 450g will be the better option to buy as I'm changing the 160-180 litre system every week? I think I may flip to 12/12, soon is it safe to use throughout flower?

I think from now on I will keep a tub of this for the future, and make sure its it's put to good use!

teaspoon ( 5ml Scoop) for every 50litres of water mate , once you have it in the system pour it through your net pots to get to the roots but you cant overdose so if you wanted to add more then its okay. BTW I only know this because the Boss ( Han) gave me the same advice when i had a light leak

sorry and you should use it all the way through your grow

ATB