ebb and flow vs constant flow

[glenn wilkerson]

simple question almost which one is better

[TCLynx]

Make sure that your water isn't flooding over the top of the gravel and that your plants are getting enough light and air around them.  Many herbs and squash will suffer if the ground right around the stem is getting too wet, you may need to add more gravel or lower the flood level.

[Sylvia Bernstein]

Allisyn, can you include some pictures of your mooshy plants?

[Allisyn Wood]

TC, I'll try to add some more rocks around the stems. It's definitely a little low.

 

Sylvia, I'll try to add some pictures, but I'm not too good at it (old, slow computer issues). I think TC is right.  I'll keep you posted.

 

TCLynx said:

Make sure that your water isn't flooding over the top of the gravel and that your plants are getting enough light and air around them.  Many herbs and squash will suffer if the ground right around the stem is getting too wet, you may need to add more gravel or lower the flood level.

[Sylvia Bernstein]

She usually is 

[TCLynx]

I've managed to kill quite a few things myself so know many of the signs.  Most plants are a bit resentful of water flooding over the gravel, much more so than simply "wet feet"  Most plants that people tell you "hate wet feet" we might take that to mean they don't like constant flooding but the truth is many of those plants will do just fine in a constant flood bed as long as there is a good enough dry layer of gravel above the "flood" height.  I've even grown citrus in a constant flood bed and they are supposedly totally prone to trunk rot in wet conditions.

[Iron Gamer]

I am also curious about how often water should go through a grow bed. The pump on my system runs once an hour.  It takes 4:30 minutes to fill the grow bed and 12:00 for it to drain.  So the bed is dry for about 48 minutes each hour.

 

The last few months I have had no success with bacteria showing up.  This system had been running without fish for months.  I then added some fish which all died.  I'm now on my second group of fish (tiny 15 cent Petco wonders) and they are starting to die off.

 

The nitrate/nitrite levels have always read zero in this system.  Currently the ammonia levels are between .25 and .5 ppm. Which is toxic at the pH level of the systems water, more on that below. The water temperature is anywhere from 62 - 72 F during the day.  There is a 50 gallon aerator in the fish tank.  The fish tank sits with 40 gallons in it when the pump is not running.  The fish tank is drained from the bottom using a piece of pipe that extends to bottom and has a baffle on the end.  The entire system is inside a small hoop house.

 

Is there not enough light for the fish? I've thought of cutting a different drum so it could sit on its side, which would allow much more light into the tank.  

 

The pH of the water is 8.2 and is strongly buffered.  The well water used for the tank reads 8.  I have put some of the lava rock and pea gravel that makes up the media in vinegar to see if there is any lime, no bubbles.  I have tried a number of natural items to lower pH but it doesn't move or bounces right back. I finally picked up some pH down which doesn't seem to do much either, the pH bounces right back.

 

Here are some pictures of the system.

 

[Sylvia Bernstein]

Your timing cycling is fine.  I'm curious about your system running with no bacteria showing up.  Was your system ever fully cycled or is it brand new?  Were you adding some form of synthetic ammonia to attract bacteria to your system before you added the fish?  Your fish may just be dying off because they are cheap feeder goldfish and were not raised with the intention of living a long life.  I've never had good luck with those $.15 wonders...and I've tried many times.  They don't really need much light, and your pH isn't a big problem for them, and your ammonia levels are low so they aren't dying from that.  If that 2-outlet aerator is the only thing providing oxygen to the tank that might not be enough - you may want to figure out a way to add turbulence when the water is re-entering the fish tank.  If you are swinging your pH up and down a lot that will definitely harm your fish, and perhaps kill them.  Try to only move pH about .02/day when fish are present.  Your high pH problem is mostly likely caused by your water - well water is typically very hard, loaded with minerals and difficult to adjust.  The best solution, IMO, is to put some sort of RO filter on it.  Short of that you will probably need to fuss with it daily until you get a good bacteria base which will help you keep it down...although that may not be the final solution.

 

Hope this helps!

[Iron Gamer]

Thank for the reply Sylvia.

 

I also posted this as an update on my system thread and Harold Sukhbir dropped in the tip that citric acid kills off the bacteria as noted in this thread http://aquaponicscommunity.com/forum/topics/our-im-in-over-my-head-...

 

I did try using Lemon Juice and some pH down, so I believe that is why no bacteria have shown up. I'm going to dump my current water and flush the media bed a number of time and set everything back up and see how it goes.

 

As for the 2-outlet aerator, it is supposedly rated for a 50 gallon tank, my tank has 40 gallons in it most of the time. The aerator runs 24/7. Do I need more?  Currently when water enters the tank it falls a few inches, any leads on how to increase the turbulence if it is needed?

[TCLynx]

I would run the pump more often or even constantly during cycle up.

 

With really hard well water, you will have alot of excess calcium carbonate in the water that will buffer the pH up and it takes quite a lot of acid to dissolve that all away.  Many people are switching to RO filters to make pH easier to control.  Another way to go about pH adjustment would be to use that extra barrel to prep your top up water.  You could draw the water and then use muratic acid to adjust the pH while it is not in the system.

 

You don't want to adjust pH in the system since it is likely to bounce with alot of calcium carbonate buffering it.  You will probably need to add acid several times to the barrel of water and let it mix before you will get the pH to come down and stay down.

[Gary Collins]

Hi Allisyn,

What size siphon you using? I thinking about changing my bed to a ebb & Flo with a 1" siphon drain to make sure the bed drains faster than the fill cycle. Right now it's constant flo and my plants didn;t like it.

 

G

Allisyn Wood said:

Hum... My system is only a couple of months old so the muck shouldn't be a problem... it takes about 15 minutes for the beds to fill and only about a minute or two to drain, so it should be getting some oxygen sucked down into the roots.   I can't really change the timing on the cycle as the flow is perfect to kick the siphon.  Anything less wouldn't work.  Been trying that... I'd rather put the thing on an indexer, but still trying to figure out that one.

[Allisyn Wood]

Hi,

In the three beds I have right now, I have 3/4" pvc as the main pipe with a piece on top that fits into a 2" bell pipe for the initial funnel thing. I would like to have like to have gotten a bigger funnel, but wouldn't have fit inside the 2" bell and therefore, inside the 3" pebble screen PVC piece.  I have a piece of rubber hose inside to create yet another "step down" (saw it on a you tube video from hydroponics4life ). I think this helps a lot, but don't really know otherwise.  Seems like more is better when trying to suck water out of a 55 gallon bed at a rapid pace...  I like this size in the two smaller beds (I chose this size because I didn't want a big 4" PVC piece for my rock guard to take up precious space).  Next time, the big bed will have a larger (1") siphon with the 4" rock guard.  So far it works great, although it was a little scary in the big bed when we were first setting up.

Hint:

I used marine grade silicone to GLUE the 3 or 4" rock guard down.  It keeps the little pebbles from wiggling under it and messing the whole thing up.  I can only offer patience with this.  LET IT DRY!!! I got overzealous (twice) and it took another effort (and 24 hours) to finish the thing before I could even fill with rocks (because they'll push it around while it's setting and if your rocks were like mine, there were already wet...)  Because of the malleability of silicone, it would probably come loose with a good wiggling, but so far, it works for what it is.  My hands are small so I can still get inside 3" if necessary, but you might consider this if yours are bigger.  Issues are bound to happen.  I do NOT have my siphon pieces glued to each other so it is removable if necessary to get to the bottom and remove debris if necessary.

 

I am not on a timer, so my beds fill up about every 10 to 15 minutes.  I wish I had a timer or even better, an indexing valve, but as of now, it is what it is...

 

Good luck!

 

Gary Collins said:

Hi Allisyn,

What size siphon you using? I thinking about changing my bed to a ebb & Flo with a 1" siphon drain to make sure the bed drains faster than the fill cycle. Right now it's constant flo and my plants didn;t like it.

 

G

Allisyn Wood said:

Hum... My system is only a couple of months old so the muck shouldn't be a problem... it takes about 15 minutes for the beds to fill and only about a minute or two to drain, so it should be getting some oxygen sucked down into the roots.   I can't really change the timing on the cycle as the flow is perfect to kick the siphon.  Anything less wouldn't work.  Been trying that... I'd rather put the thing on an indexer, but still trying to figure out that one.

[TCLynx]

If your siphons are working, then you are fine without the timer.  When you get to the point of switching to a timer/indexing valve system then you will probably need to switch to standpipe drains and skip the siphons.