Backyard Aquaponics
A place to discuss aquaponics

Running a pump continuously... that isn't rated for such use, will wear it out very quickly...

I'm wondering if switching a continuously rated pump on/off repeatedly might also shorten it's lifespan??

Some pump intended to run continuously being turned on and off constantly are going to die sooner. Kinda depends on the pump and how often it is being switched on and off.

As to the running the pump on a timer and yet having a siphon in the mix but also a slow drain. This could be made to work though it might take some extra tinkering to get it all balanced right so the siphon still kicks in even with the extra dribble of water draining through the slow drain.

I believe some people have the continuous run with siphons and have also put in a slow drain to slowly drain the bed in the event of power out so the roots are not left sitting with wet feet too long. This would also slow the cycle times down a bit cause it would take longer for the bed to fill.

However, I don't know that there would be much benefit really to trying to go hybrid between siphon and stand pipe operation with a timer. Probably just easier to set up the stand pipe and add holes till the drain time and fill time work out the way you want them to and use the timer.

I have been a firm believer in continuous run and siphons for a long time. I do believe it delivers more constant filtration for the fish and being able to have the pump running continuously for the aeration is great. Problem I'm seeing with siphons though is that the bed never fully drains because as soon as the siphon shuts off there is still water flowing in and even if there were not water flowing in, siphons still shut off while there is water in the bed and the flow rate through the gravel will affect how early the siphon shuts off.

Now I'm beginning to believe that the plants at lest would like a little more "dry" time (not really dry but not flooded.)

So, to some extent one method might be a bit better for fish (constant) while the other method is probably better for the plants (timed). I expect bacteria are probably happy either way as long as the "dry" time doesn't actually let them dry out.

I'm trying to work out how to have both (continuous pumping/filtration for fish yet timed flood n drain for the plants.) without spending too much extra money.

Hey TC

my beds are F&D with a timed pump and siphons ....

my pump runs for 8 minutes which fills the 3 beds and at around 7 minutes the siphons start...

so far works really well.... it did take some playing around to get the start times correct...

I also have a weep hole in all the siphons, so the beds drain down to about a quarter of an inch...between fills

jT

Yep JT you be one of them timer and siphon types.
But with the size of your pump, I don't think you could do it any other way!!!

Well you could just do pain old stand pipes but then you wouldn't have gotten the fun of playing with siphons.

I had something like that going on. My bed was not draining fast enough anymore so the siphon would break and leave the bed half empty(or half full?). I added a small tube to trickle down the rest. I just added a drain valve to quickly drain the whole bed. Some crops will do better with less soaking time.

TC, wouldn't having a bed that cyles every 8 mins have more dry time than say flood for 15mins and slow drain for 45 ? Plants would be only getting wet for 2-3 mins and 5-6mins to dry as appossed to 15 mins of wet and then by the time it has drained past the roots might work out to be a total of 30mins wet and then 30mins dry. Not sure but just my thoughts.

I think the auto siphon with the 6mm drain hole sounds like a good idea as it would probably overcome the occassion probs when autosiphons stuff up and may even help reset them?? Going to do some experiments......

Music to my ears - keep us informed

Yep there are so many ways to do things.

The 15 minute on and 45 minute off cycle (depending on the flow of the pump and all) often means the grow beds are only fully flooded for a short time and spend most of their time filling and then draining since the goal is to have them completely drained by the end of the 45 minute off cycle.

With Auto siphons and continual pumping, the bed is never completely drained since there is usually at least and inch or two of water in the bottom when the siphon shuts off and it is immediately filling again. This does give more continual bio-filtration for the fish but some plants don't like it as much. I've only had plants complain to me though if they are planted right next to the inlet and getting too much water over their roots all the time. I've found it is better to plant tomatoes a little further from a single continuous inlet.

As to putting a hole in the bottom on a bed with a siphon, if running continuously, you might need a bit more flow into the grow bed to be able to kick off the siphon since some water is escaping early. I don't know what effect the hole would have on helping to stop a siphon or not.

I have my bell siphons set up with the weep hole in the bottom of the standpipe. The holes are only small and the effects of doing this are:

1. Slightly longer fill time due to some water escaping before the siphon kicks in.

2. My drain pipes trickle continuously between the actual siphon events.

There is no effect on my syphons kicking in or out.

All the water that enters the growbed still has to pass through the highest point of my drain pipes (where the siphon is created) so whether it exits the growbed by going over the top of the stand pipe or through the weep hole in the bottom of the standpipe make no difference to the siphon kicking in. If I make the weep holes big enough I can make the siphon happen before the water even reaches the top of the standpipe.

My siphons kick out due to air being sucked in under the bell or through an airline; both of which are above the level of the weep holes. The weep holes do no assist or hinder the breaking of the siphon.

I run continuous pumping, for my trout set-up, trout love the flow and they need very high oxygen levels. Since I run continuous auto siphons were an obvious choice. I also run serial growbeds to increase the ratio of GB's to water but Last year I lost most of my trout due to failure of the switching setup, it half filled both GBs and shut down the pump as the sump was empty. Since then I have added the slow drain to the siphon set-up to help prevent this. I have also altered the switching unit to switch to the next GB once the current siphon has kicked in and emptied by one third.

My biggest problem with auto siphon in my set-up is that with my flow rate if I pump continuously into the bed it wont break properly and continues to empty the newly pumped in water. I tried air tubes but they did not work for me, I noticed a set-up that tclynx drew for someone the other day and it would work but since I use the slow drain and switch the pump to the next GB it breaks the siphon and drains the bed.

I also agree with tclynx in that I like the constant flow CHIFT PIST setups, however my newest system uses a timed switching between serial GB's with a faster fill and slow drain instead of siphons.

Well I have done some experiments and have found having a 6mm hole in the bottom of the stand pipe to allow continuous definateley helps auto siphons. It does not appear to require any extra flow to start the siphon but does take a little longer to fill of course but that does not really matter as the fill time was around 9mins and now is few extra mins which is fine as far as I'm concerned. Some beds which I had to insert some poly pipe into the stand pipe to help start the siphon is now no longer required, and as far as breaking the siphon it seems to break much easier than without the hole in the standpipe.

For those who are having trouble with the siphon not breaking and continuing to siphon new water entering the bed I have found that to be too much flow of new water coming into the bed and as I just said the 6mm drain hole in the stand pipe seems to make all of that better.

Although I have a leaning to using auto siphons for the more rapid water draining for the grow bed, my second system isnow setup for slow drain 15 on/45 off whilst my first system uses the autosiphons on continuous fill just so I can monitor any difference to things and also because my second system is outside the green house and expect to turn of cycling at night at necessary times throughout the year - (like frosty nights) to help keep water more stable.

So thats my 2 cents worth

Getting back to nitrates and such. I think Friendly's was trying to lower the nitrates because plants use ammonia and nitrites more readily than nitrates. I read that somewhere a long time ago when I was trying to learn about NFT systems.

From all my years of aquarium keeping I've learned that biological aerobic filters like trickle towers and such are nitrate factories that convert ammonia and nitrite very effectively and in turn dump loads of nitrates into a system. This is why 'live rock' is currently a huge trend and everyone is dumping their wet/dry filters (trickle tower) in their reef tanks. The nitrates are converted into gas by anaerobic bacteria living deep within the live rock. So using these types of filters will not remove the nitrates. I don't know about the sun and converting the nitrates to gas but sounds interesting (even magical). Maybe this is what is happening on some level in E+F GB's. Somewhere there are anaerobic bacteria using up the nitrates.

Very few plants take up ammonia directly and perform nitrification within themselves... and none do so from nitrites (AFAIK).... the principle uptake is via nitrates...

If the Friendlies were trying to lower their nitrates... they were doing so because they had insufficient plants to utilise them...

So, like aquaria or RAS tanks... the continual buildup of nitrates could only otherwise be dealt with by water replacement...

The off-gassing of nitrates, via various methods... relates effectively to the conversion of nitrates, by de-nitrification.... to Nitrous Oxide (NO2)... usually, by the very nature of the process.. a reduction process... removing oxygen from the system... anaerobic by name/nature...

In flood & drain growbeds (ebb & flow - to the old hydroponicists)... nitrates are removed by plant uptake... within an aerobic environment...

P.S... trickle towers are generally quite poor nitrifiers... in terms of nitrification to nitrates... often holding nitrite levels for extended periods of time... unless oxygenated to allow the nitrification to nitrates...


They perform reasonably well as cooling towers...

Sorry I forgot to add my question.

On a timed system with a larger pump, larger standpipe, and larger drain holes I could get even more water flowing through my system (higher turnover). Knowing this could I have a smaller growbed than the recommended ratio of 2:1? My thinking is that like a fish tank filter the higher the turnover rate the more water that is being 'processed' by the filter (GB).

The only thing I could see being a problem is that I would be adding too much solids for the GB (and worms) to handle. Do you guys (and ladies) think this is possible? Can I use a smaller GB with a higher flow rate to 'feed' the bacteria more and have a more effecient system.

I ask this because I have a small GB (55 gallons) on a 110 gallon fish tank and I'd like to add more fish without adding more growbeds.

I wouldn't use a GB less than recommended.
I pump continuously, and have no problem with gunk build up.
Gunk buildup is akin to over feeding or under-takeup by the plants in your system.
My system is on the high side of fish load but all is good.
...and yes I feel the more pumping is like more filtration
C1