Under gravel filters: upflow vs downflow?

[combatwombat]

ha, you make me laugh, CW; I'm SURE I read, somewhere in this GB-length thread, that you were going to eschew a waterfall in this build! Did I imagine that?????

I've eschewed and then uneschewed lots of things. Haha. No one is going to know what this pond really is until its done. Including me.

Are you also going to have a skimmer?

Yep. Negative edge / infinity edge skimmer.

 

[Jhn]

@Jhn: That line of thought makes sense. The main reason I'd be interested in a suction grid is because it would mean I get to send more water to another waterfall!

Fair enough.... nothing wrong with more pump power.

I've eschewed and then uneschewed lots of things. Haha. No one is going to know what this pond really is until its done. Including me.

I think that is how most of us are that build our own ponds, I know my pond changed quite a few times while I was in the middle of building it. Always coming up with better ideas even while digging.

 

[GBBUDD]

Many have made mention to my build getting too big too many pages. When i was looking at building my pond there was a little info here a little there and some over there and it became a nightmare trying to find it all. i originally was going to break up the blog in phases but changed for the reason above. I am thinking about putting together a build only blog take the build and shorten it removing the conversations etc.

 

[Lisak1]

I have always been intrigued by the idea of an under gravel grid filter - back to aquarium days I guess. If I were going to do it in a pond, though, I'd want water pushing up. I've always loved the idea of a whole pond full of tiny bubbles rising from the bottom... Weird, I know!

Here's an idea for your brain to ponder - build it so it can go EITHER WAY! Push water in or pull water out... how hard can that be??

 

[brokensword]

I have always been intrigued by the idea of an under gravel grid filter - back to aquarium days I guess. If I were going to do it in a pond, though, I'd want water pushing up. I've always loved the idea of a whole pond full of tiny bubbles rising from the bottom... Weird, I know!

Here's an idea for your brain to ponder - build it so it can go EITHER WAY! Push water in or pull water out... how hard can that be??

dayum, @Lisak1 ; you're giving CW MORE ideas????? His brain'll explode at this rate!

 

[GBBUDD]

While i do like having the main drain and i do have a thin layer of stone on the bottom laying on fabric. the fish turn over the rocks thus dislodging any sediment that may have settled. and it is then sucked in by the two main drains.
Pro's
helps keep the bottom clean
helps keep the bottom clean

Cons
A penetration in your liner if not done correctly could become a night mare

I have lost large and small fish due to the power of the drain.

The main drain in cold areas should not be used as it keeps the crucial area at the bottom THAT SHOULD BE KEPT STILL so your fish have a steady temp at the bottom and a constant.

 

[GBBUDD]

dayum, @Lisak1 ; you're giving CW MORE ideas????? His brain'll explode at this rate!

Naaaa cw i get the feeling was the kida kid who couldn't be stopped and never stopped . He is doing the homework for all those who come here that do next to none ..

 

[brokensword]

Naaaa cw i get the feeling was the kida kid who couldn't be stopped and never stopped . He is doing the homework for all those who come here that do next to none ..

sniff; sorta wanted to see it happen, GB; spoilsport...or at least how close we could get him...

 

[combatwombat]

@Jhn / @Lisak1: Just read about a study that was done between under gravel suction vs. pressure grids and result = they both clog up the same.

Found it on computer and in phone right now so can’t link to it, but found it while reading an old thread here about Anoxic filtration and comparing different filter strategies.

 

[GBBUDD]

Cw i don't know IF YOUR AWARE OF @Meyer Jordan HE WROTE ALL KINDS OF POSTS THAT WILL DEFINATELY GET THE CERATONIN PUMPING

 

[combatwombat]

Cw i don't know IF YOUR AWARE OF @Meyer Jordan HE WROTE ALL KINDS OF POSTS THAT WILL DEFINATELY GET THE CERATONIN PUMPING

Only know of him from the Easter eggs of wisdom he dropped around here in the past. Glad he made time to share them.

 

[Evguy1]

'm just starting a new pond, excavator is coming tomorrow. It will have a 60 X 50 foot pond connected to a 30 X 40 bog for filtering. I liked the idea of a bottom suction grid but have been looking into airlift pumps. Will an airlift pump be able to pull water from the bottom of the pond and pump it through the bog pipes to then flow out the top of the bog and back into the pond? The bog will only be a few inches higher than the pond.

 

[combatwombat]

'm just starting a new pond, excavator is coming tomorrow. It will have a 60 X 50 foot pond connected to a 30 X 40 bog for filtering. I liked the idea of a bottom suction grid but have been looking into airlift pumps. Will an airlift pump be able to pull water from the bottom of the pond and pump it through the bog pipes to then flow out the top of the bog and back into the pond? The bog will only be a few inches higher than the pond.

Have fun digging! You brought up two things: suction grids an air lifts.

Surface areas of holes for a suction grid should be evenly spaced and add up to about 10x of the diameter of the pipe used. I decided to go with pressure grid. Like having a second bog at the bottom of the pond, and less risk of clogging.

Air lift can move lots of water with little energy, but they lose flow fast once you go above water. If bog water level is only a few inches higher, you can probably make it work. Probably want to use same 10x surface area of pipe for your pipe grid in the bog. Don't restrict the flow—air lifts don't work well with much friction loss. Depth of submergence is key as well. The deeper you can make your lift pipe, the more flow you'll get.

 

[Evguy1]

Have fun digging! You brought up two things: suction grids an air lifts.

Thanks for the feedback. I had read a few of your posts on both subjects and thought you may have the answers.
I could not figure out how to do a bottom up bog with a suction grid and airlift? If the piped in the bog are large enough you think it should work? Pump the water up just to the top of the bog and then let it drop down to the grid in the bottom of the bog? We dug this last Sept and hoped it would hold water but its now dry. I just ordered a 50 X 100 liner so were enlarging the hole today to make use of all the liner. I just started to read about air pumps and love the idea just have not found one running from a suction grid to a bottom up bog. I suppose if it did not work I can switch to a conventional electric pump after the fact.

 

[Jhn]

I wouldn’t have a suction grid at the bottom of your pond feed into your bog without some type of settlement chamber.. Not that it won’t be able to do it, but the point of a suction grid is to keep the bottom of the pond clean and debris free. You do not want all that crap getting pumped into your bog, it will clog your bog up quickly.
Personally, if you want a suction grid I would just do one separately the. Have a pump feed your bog from up off the bottom.