I built this about 3 weeks ago and need some advice (put all my soil pots away). It is a flood and drain 100 Lt bottom res. and 30 Lt top res. I have the pump run 30 min and off 30 min. There is no media in the bottom of the top res as roots just hang out the net pots. There is an air stone in bottom res that runs 24. I am using Higrow nutes and an running at about 950 ppm TDS. My base well water is around 250-300. PH was a real issue at first but I seem to have that under control as it is running between 5.5 and 6.5. My questions are as follows. First like I said PH seems to jump up daily and I add a capfull or 2 of PH down as I am trying to keep it at 5.5 is this ok? My TDS seems to be stable but it does seem to be slowly climbing, is this normal? Is my timing for pump ok? I also add 50-60 ml of power zyme once a week, is that a good practice. I am running 4-4' HO T5's but will probaly switch to a 400 HPS for budding in a week. Also (and lastly lol) should I be draining system weekly or just keep topping up.? Thanks for any help? Oh and the girls are serious seeds white russian at 3.5 weeks from seed
Hey Waterdawg! I'm a flood/drain fan and have made any number of these devices, kudos on your effort! Nutrient and water uptake most efficiently takes place as a mist...the mist forms after the drain and the water that's left on your rocks begins to evaporate. I like to flood for only as long as it takes to start draining at the overflow, then shut it off for a couple hours. Lately, I've had trouble with timers and find that the mechanical 15 or 30 minute increment timers are just damned reliable, so I'm currently flooding for 30 minutes every 90 minutes. I'm sure there are others that could help you dial that in a little better, but that's what is working for me at present. Your water is somewhat hard, if you could use reverse osmosis it may help your pH swings a great deal. I have no experience with your nutes. Targeting 5.5 is fine, and it is normal to have some movement especially in a fresh res fill. If TDS is climbing, your reservoir level is likely falling, be sure to top off with clean, pH adjusted water. I use the Lucas formula because it's simple and requires no additives, don't know about your power zyme question--I'd say follow the directions on the bottle. I think switching to the 400 is a great idea...as soon as possible! Let them veg at that wattage for a week, then switch to 12/12. Using the Lucas formula, it is possible to keep the same res for an entire grow by topping with clean water and adding back nutrient to bring TDS back to your target -- In my case 1000ppm @ .5 conversion. Otherwise, it's a common practice to top off with plain water until you've replaced the original starting volume, then dump and start fresh. I'm currently running Serious Seeds White Russian! When flowering from seed you will definitely see stretching when you make the switch. If you could possibly pull one of those plants to use as a mother and start cloning, you'll have very consistent, short on stretch plants that will keep you happy! See my journal for a couple WRs from seed that just went nutty. I've not been keeping up with the journal at all...but harvested those from seed - the space was hot, the plants got too close to the light, the buds were fluffy and lacking. I've had a run of 8 clones since then - at harvest they were under a half meter tall and produced nearly 2 ounces per. ...all of this just to reiterate the importance of switching to the bigger light and get to flowering before they get any bigger! Alright, I've praddled on long enough. Take it, leave it, whatever works for you! If you'd like to read more from Lucas, check out the link to the Ask Lucas Knowledge base...there's a wealth of info there!
Thanks Casual. Great help as I have been kinda lost as it is my first try at hydro. I am also using a mechanical timer on the pump. I have nothing in the bottom under the net pots. Should I fill that with hyrotron to achieve more evaporation? Concerning the light I did a side by side comparison of both a 400 HPS and the 4 T5's with my last grow and there was no visible difference in bud development which was a surprise. In saying that I am going to switch as I need the T5's to start the next tub! I had planned on cloning the best of this batch but am running low on reserves (been a long hot summer) so I am going to move these ones untouched and clone the next batch. How many pheno's did u have? I do have some Kannabia Mataro blue that I will start next as I really like the strain re: taste and high. After they are started I will throw in another batch of WR. I also will hook up the CO2 this weekend in the bud room to give them a boost. The nutes that I used are mixed locally so not very well known but seem to work good. Should I use my base water TDS and add nutes to bring it to like 1250-1300 which would give me a 1000 ppm nutes?. Again thanks for all the help!!!!
I wouldn't add hydroton to the table, that would encourage too much moisture to linger and your roots would make their way into your fill/drain lines. Lots of healthy roots, good...roots clogging lines and pumps, not so good! Lighting, if it ain't broke... I had two distinct phenos. One that stretched, but stopped after a bit. The other continued to gain height nearly all the way through flower. You'll need to know if your TDS meter uses a conversion of .5 or .7 to know whether your target is 1000 or 1400. Short of knowing the conversion and if you're already using your nutes at 1250-1300 without any burn, you're golden. I've seen people argue include the starting ppm and others say do not. I will always err on the side of caution and include it (until I started using RO water and it became a non-issue!). The Ask Lucas Knowledge Base | EC/TDS - some info on TDS and meter conversions. Hope this helps!
Wow great read! Thanks! I have just moved the girls under 12 today and probably should have done it 3 or 4 days ago as the growth rate is phenomenal! Started another tray today of Mataro Blue and a couple of clones from the bushiest WR. My luck I probably picked a crap pheno but oh well. Some things are starting to make sense now after reading. I have 2 meters, one measures just TDS and the other measures, salt, TDS, conductivity, PH. I was always getting a higher reading from the multi tester (1380)so it has a .7 conv. and the TDS meter has a .5 (990) due to conductivity is at 2. So I still am really confused that my PH goes up and actually my TDS is only dropping very slowly, but am not stressing as before due to the girls seem to be really happy (try to post a pic tomorrow). I did drain the res and add bud nutes but this was before Lucas...lol. I will price out a reverse osmosis system this week but will probably stick with well water for now. I dont have access to water and have to keep a 350 litre tub filled, but will soon run a line and keep the tub filled by float valve. I still am not sure if I need to add anything in the top res to keep the roots off the bottom but will maybe try with next tray. I'll let them grow for 3 weeks and then turn them down to 12 and am hoping to get a tray done every 4 weeks once I get rolling........ if all goes well! Again you've been a great help as I was totally lost, thanks!
Actually I read some more.... lol.... and will give RO some real consideration to use to fill the tub. I now get the PH rising thing due to my well water. I also live on a lake so will check that level as well.