Backyard Aquaponics
A place to discuss aquaponics

well i just bought a 10x20 greenhouse!!! I just need to buy an IBC and some blue barrels and i can get started. I was wondering if it is better to use a sub pump or and external pump, i thought maybe fish could get get sucked into the sub pump(For pumping from fish tank).

external pumps are good if everything will be above ground and you are very confident in your plumbing skills to hook up a pump externally and not have the tank it is drawing from leak and drain out at your plumbing.
Some people insist that external pumps are more efficient but that is probably only true when you are talking about very large scale systems.

If you have an in ground tank or sump, using an external pump can become quite difficult since most of them are not designed to suck water up and installing an external pump in a pit makes it difficult to access and if you are in a place where the pit could flood during a heavy rain event, putting an external pump in a pit could be a very bad, even dangerous idea.

For small scale systems a submersible pump is often a perfectly fine idea. Not necessarily a sump pump mind you. There are many small mag drive submersible pumps that are probably far more efficient than the average sump pump (which I assume that is what you meant by sub pump.)

Be sure you look up the pump curves or head hight charts on any pump before you buy it. You need a pump that will deliver enough water flow at the height you need it to pump to. If the box says 300 gph and Max height 6 feet or something like that, you can bet the pump won't be moving anywhere near 300 gph at 3 feet. The max head is the height at which the pump no longer moves any water and the gph rating on the box is normally at 0 head. Look for a pump that actually tells you how many gallons per hour or gallons per minute it will pump at different heights. Pumps are generally most efficient when working in the middle third of their range. Also, a cheap pump usually won't save you money since they often cost more electricity to run and you will likely have to replace them more often. spend a bit more money up front getting an energy efficient pump that will last and be suitable to your system size.

You need a pump that will move AT minimum the total volume of your fish tank at the height needed during whatever portion of the hour the pump will be on.

Thanks for the advice! so i am thinking that i should do a fishless cycle but how do you give the plants nutrients if theres no fish?

During the initial cycle up of a system some nutrients may be in short supply for the plants weather or not fish are in the system. Usually some seaweed extract helps take care of the trace nutrients that are in short supply in a brand new system.

And the truth is, the fish don't provide the nutrients to the plants, it is the fish food you feed to the fish that ultimately provide the nutrients.

"And the truth is, the fish don't provide the nutrients to the plants, it is the fish food you feed to the fish that ultimately provide the nutrients."

lol find that in a fortune cookie? just kidin. yeah i get that but ultimatly i cant but fish food into my tank and get nutrients for my plants. Would you recomend doing the first cycle with quick plants like lettuce cus i feel like other plants wont do so well without the nutrients? could you use ammonium nitrate to put alittle ammonia in the system while also providing nitrates to the plants?

Remember that a lot of plants don't need too much nutrient right at first. But you are right in you probably don't want to go planting too many of the greedy or flowering plants during the first several weeks of cycling up a system.
I probably wouldn't go using ammonium nitrate as it will make it hard for you to test for nitrates to know when the cycling is getting under way. But don't get too wound up in it, that initial part of cycling (when there are little or no nitrates) usually only lasts a few weeks and then the rest of system cycle up usually takes another 3-6 weeks to get the bio-filter up to speed. Most plants spend at least 3 weeks as "seedlings" when they are only using small amounts of nitrate and you can add some seaweed extract to help provide a lot of the trace nutrients that the plants need early on when the system is young.

Many people do recommend sticking with mainly greens and easy things like lettuce in a new system. I think part of that may have to do with the limited nutrient availability but part of it is just that people tend to get impatient when they are not seeing results so growing some of those fast, easy plants helps provide some tangible results people can see and ease their impatience.

I had no luck with lettuce my first year. The chard did okay until the ants started farming aphids on them. They certainly did not have growth like they do this year. The tomatoes did not do as well last year, but I think hat had more to do with the variety than anything else.

good to know. Would adding nitrogen fixing bacteria to the water help?

If you cycle up fishless, you are going to have plenty of nitrogen in short order so I wouldn't worry much about adding extra nitrogen in the beginning. It is all the other nutrients that can be missing when all you are dosing is pure ammonia.

can you buy an ammonia solution?

Yes, it is called ammonia.

99¢ Only has big jugs of pure ammonia, and since it is only 99¢, that is probably the cheapest way outside of humonia to cycle.

sweet. sounds good.

Now if you have trouble finding pure clear ammonia (ammonia that has no dyes, perfumes, or detergents in it, shake it and make sure it doesn't foam up.) you can order ammonium chloride online and it comes in powder form so is cheaper to ship and less stinky to dose. Mind you, don't dose enough to make your system smell like ammonia but there is no way to escape the ammonia smell when you pour a little ammonia into your measuring cup or spoon (depending on system size)

If you use ammonium chloride powder you will probably need a scale that can measure grams since you only need about 1.13 grams to dose 100 gallons to 1 ppm. You might want to find a source that is willing to measure out doses for you based on your system size if you don't have a sensitive small scale handy.

This is interesting. I think it also makes sense to plant to seasons and conditions. i.e. planting corriander in summer will bolt very easily, or planting beans in winter will make them shrivel and turn yellow.

I'm struggling to get onions to work in my A.P. System.