Size of filter I need

[Tr1951terry]

Hi can anyone advise me please size of filter for my 1800 litre pond I’ve been told bigger the better I want to run a blade waterfall 45cm wide I’ve seen 2 but I’m not sure which one will be best the pond is a raised pond 6ft x 5ft x2ft I do have a smaller pond I built and a 1500 litre filter but it’s not powerful enough for the blade

 

[brokensword]

Hi can anyone advise me please size of filter for my 1800 litre pond I’ve been told bigger the better I want to run a blade waterfall 45cm wide I’ve seen 2 but I’m not sure which one will be best the pond is a raised pond 6ft x 5ft x2ft I do have a smaller pond I built and a 1500 litre filter but it’s not powerful enough for the blade

general rule of thumb is to turn the water over 1-1/2 times per hour. The first pump notes its output at about that--2500 lph, the second says nothing. So, I'd opt for the first.

Now, further considerations and I don't know how far into this you've got, so bear with me. ANYTHING underwater, is going to be more of a pita to service. Might not bother you initially, but it gets old over time. So, make this easy to service, which MIGHT mean considering something like a bog filter (for many many other great reasons besides the fact you DON'T have to service it other than thinning plants occasionally).

Second, you don't need the UV if your plan includes options that challenge whether free floating algae (which is WHY these companies include the UV light as these two models seem to have) that typicall happens when you don't plan for it. Again, a bog and some surface coverage will help you immensely.

If you haven't already got the idea I'm trying to lead you down the bog filtration path, to search here and do some reading then decide if you want either of these two filters, then I'll flat out say it; a bog filter will cure a LOT of common ponding problems.

So, MAYBE you DO go the bog route; you'll STILL then have a question with regard to your blade and pump output/power, right? So, let's head there...same rule of 1-1/2 times turnover applies, so IF you were to get just a pump now, get something in the area of 2500 lph. That said, let me now nudge you to go bigger, simply because pumps will pump their output but start getting cranky when you want to LIFT this water output into the air and over the pond surface. This is called head pressure (along with ALL and ANY fittings, hose, etc attched, this creates a backloop of force which will drop your output lower than you want/intend). So, how high your blade is ABOVE the water surface + plumbing hose type + hose fittings will determine what you want. It CAN be calculated but it's just a lot easier to do this; get yourself the 1-1/2 X pump, put a LARGER adaptor on the output end, then a wye or tee which gives you TWO leads. On each lead, put a ball valve. This gives you control. You'll then either send all or part of your output to your blade DEPENDANT on what your vision IS for this blade. Low flow, hight flow, doesn't matter as you control this now with the 2 valves. If you achieve what you want with one feed, the extra can go into the other and to whatever fixture or just dump into the pond as surface agitation or whatnot. Lots of leeway and options this way. The key here is the larger-than-output adaptor. In my case, my output is 1-1/2" so I used a 3" adaptor, then a wye, then two reducers (back to 1-1/2") and on to my two feeds. Got one going to a waterfall (btw, I put the ball valves AT the waterfall and AT the endpoint of the other feed so I can easily adjust; they are NOT UW and hard to get at!) and the other line goes to bog filter #1. Since I have TWO pumps, I actually have FOUR lines, 2 each for redundancy.

Anyway, long answer, I know, but wanted you to think about your choice(s) and hopefully find something easy and that fits your ultimate vision.

 

[Tr1951terry]

I got the y piece u advised before I don’t have room for a bog filter and to be truthful it’s beyond me as this is new to me my small pond has been good and easy to manage I just wanted to go a bit bigger I clean the filter regular and my son bought me a pond vacuum the water is very clear I just didn’t know which of the filters to get i dont mind getting the bigger one but didn’t know if it was to powerful for my pond

 

[brokensword]

I got the y piece u advised before I don’t have room for a bog filter and to be truthful it’s beyond me as this is new to me my small pond has been good and easy to manage I just wanted to go a bit bigger I clean the filter regular and my son bought me a pond vacuum the water is very clear I just didn’t know which of the filters to get i dont mind getting the bigger one but didn’t know if it was to powerful for my pond

ah, okay, I remember your pond now; shouldn't be too hard to service either filter. I'd go with the larger because if using the valves, you should have enough flow over your blade. Better too much and control than too little and frustration! And that second pump didn't even list it's output, though probably smaller (i.e. price was less, so an assumption). You should be good to go.

One last note; IF you decide you want to TRY a bog filter, it can be done by using long, rectangular flower boxes along the top of your box, overhanging the pond box so it could pour into the pond. You'd have to put some sort of support underneath but that would be easy usng wood or metal. Again, NOT at all hard to do and you'd gain more real estate for plants you have your eye on. And these plants then would be protected from any fish predation. Just more thoughts for you as once established, you don't have any maintenance with bogs. (well okay, thinning plants, that's your maintenance). Gives you more texture and flower options, too.

 

[Tr1951terry]

Thanks for advice I’ll get the bigger one I don’t plan on transferring my fish into my bigger pond till spring so plenty of time an I’ll look into a simple bog filter I did look at a video on u tube but haha it didn’t make much sense to me told you it’s new to me

 

[brokensword]

Thanks for advice I’ll get the bigger one I don’t plan on transferring my fish into my bigger pond till spring so plenty of time an I’ll look into a simple bog filter I did look at a video on u tube but haha it didn’t make much sense to me told you it’s new to me

I'll break it down; it's really simple. The idea is you pump water from the pond into a tube that goes to the bottom of your 'bog' box. This tube portion that lies on the bottom has holes/slips in it to let water go up. It rises up through pea gravel, typically 12" deep and once at the top, pours over like a waterfall. The filtration going on here is BIOFILTRATION, which is what those pads/sponges in the filters you're looking at will have. The pea gravel has a LOT of surface area (which is the key), much much much more than those pads and sponges will ever have. It's ON this surface that good bacteria lives. THIS is what converts all the ammonia from the fish and rotting debris IN your pond into nitrites and then is converted by another type of good bacteria on the pea stone, into nitrates. This last is not nearly so deadly to fish. You put plants IN your bog top to take out the nitrates. Algae will do this for you too but most of us don't want that free floating type that makes the water green and you can't see anything. All the algae that will grow on your UW surfaces is the good stuff, and they're plants too, so they will help get rid of the nitrates.


So you see, a bog is the same as a purchased mechanical filter in all the important ways--biologically. Now, you don't want to put your pump on the pond bottom as it will suck up debris and send it to your bog which WILL cause problems because a bog is not meant to filter that way. If you want to filter larger particles like that, you'll need a pre-filter before the bog (which btw, I have and if you want ideas about that, let me know, but it's not necessary if you keep the pump high as suggested. Most don't use a prefilter, I'm just over cautious).

The really really GREAT part about bog filters is you have very little maintenance and because they offer so much more area for the bacteria to colonize, you get a lot more benefits and it'll handle larger fish loads than any mech filter you'll see online.

 

[sissy]

I really prefer a home built filter as those filter pumps are heavy and really are not the best . When that filter gets dirty it gets even heavier to take out of the pond . But now it is hard to get anything these days