Hi and hope you can offer some advice.

[Nature Discovery Villa]

Another thing total depth of both steps is 20 inches to the water level the blocks are 7 inches high so in theory the wall will be slightly higher than the water level is this OK so I fill with the pea sized gravel to the top and the water would run over the top I to the pon or should the wall be under the water level. I ask this because I have to order the blocks

 

[GBBUDD]

The total depth works of the steps but is awfully narrow. 12 inches wide can work but that leaves no room for a retaining wall . To hold back the peastone. And 24 inches wide is much better for a width but 6 inches does not work so great. Your ideal retaining wall would be as thin as possible yet strong enough to hold back the stone. Without the engineering cap coming out i guess id lean toward a stainless steel " L" a 12s inch wide base with a 20 inch tall vertical wall welded to the 12 " . Place the pieced on the lower shelf. And use a few spots to apply something to secure it to the shelf and then use the weight of the stone its self to hold the wall primarily in place. Even building a thin small inch retaining block wall takes up a lot of valuable space.
So that leaves building a new bog as possibly as your best option. But it will have to be 30 % OF THE SIZE OF THE PONDs surface area. To cheat this a bit you could go to 20 and make it deeper but you already have one design fail dont know that I'd risk a second I'm sure its already become more expensive then you'd like.

 

[Nature Discovery Villa]

Hi and thanks but now I have to really think how to do this because there is no way to put stainless steel plate the whole length of the pond. It would cost more than the pond at Malaysian prices. I will have to think of another way some how. Unless I do both sides. Right now we are thinking of only one side. If we did both sides would give more area even though narrow a bit. If you don't agree then I will look at fibreglass or similar.

 

[Nature Discovery Villa]

The next problem is the pea pebbles so difficult to get in large quantities. I can get this but not sure if it will work.

 

[GBBUDD]

The idea with using pea stone or river rock is the round edges and it allows fir some flow and for the most part won't trap sediment.
Id look at building a new bog..
The stainless was just the quick easy solution to maximize the available amount of space. even 4 inch concrete block closes the space 1/3 but a 8 inch x 18 inch channel will do its job its a question of is it able to handle the load of the pond.
I know there is rock i can get here in the states that comes from india thats a river rock. And id image there is 3/8 or even 3/4 inch river rock thats native to an area around you . Will your example work i would say yes .for a while anyways. It may start to clog over time its hard to say i never used it myself .

 

[poconojoe]

I don't know what that white stone in your picture is made of.
I would think if it were limestone, that would be a problem. Limestone may adversely affect the water Ph....I think...

I'm not a geologist, so I don't know the proper terminology for a stone that is made of soft material that might dissolve and cause problems.

But, in general, you don't want any sharp edges that could possibly puncture the liner.

 

[Nature Discovery Villa]

Ahhh now I understand about the stones. Here they sell river stone but the biggest qty I can find is 20kg bags. And that would take a lot. OK so now this is my biggest challenge. 0nce I can get the rock, I will take your advice about the inclusion of a bog filter and initially use the existing steps down both sides at least it will make the pond look nicer if nothing else. I guess it will do something and may even if not ideal be better than cleaning the filter cloths 3 times a day as I have to do now.
How long would a bog filter take to start working?
If more is required then I would have to drain the pond to take out the existing filter arrangement and build a new wall making it wider so I could add an additional bog to the end of the pond. The challenge is housing all the fish and of course emptying over 100000 gallons of water. As a matter of interest it takes nearly 3 weeks to refill.
I am sure we can do something and I really appreciate your time and help with this.

 

[GBBUDD]

Read the posts on this site about the bogs and the numerous builds. you tube atlantis water gardens , team aquascapes and john adams get all the tricks and theories A negative edge is an other very useful part in keeping a pond clean and balanced. Having a B and B with people swimming in the pond id be weary of internal monster pumps if they can get near them thats a potential disaster

 

[Nature Discovery Villa]

Thanks atlantis and aquascapes I have watched before, John Adams I don't think so. I will look.
Negative edge not sure I know what you mean there, is this the dge of the retaining wall to be under the water level?
I just realize that the dimensions given are the minimum I think. I will get my son to take a drone pic and then I will mark out widths and depths. This may help you advise me how many pipes, what size and if it will have any effect. In the mean time I will search for more drawings on this site.

 

[Nature Discovery Villa]

One of the most important things to know is in the US and UK you guys do a lot of this kind of thing, here is very few with limited if any expertise. Components are easily come by in the US here we have nothing so this kind of thing is not straight forward. Then you have total idiots like me trying to fix the contractor cock up and make it work without any knowledge at all. So I am grateful for all advice and assistance. But what ever I do will never be as good as what can be done over at your end. However I will try to make something work.

 

[GBBUDD]

One other option is to use the steps as a base and build up from there Making for more waterfalls " never a bad thing" .

 

[GBBUDD]

bog builds are new in the garden and swim pond but sewer treatment plants have done this for years. Its fairly new here it has yet to really catch on but i see a pond or water feature in the future to be every third home

 

[Nature Discovery Villa]

OK so following your design I could still utilise the second step because in places it is 16 - 18 inches wide, make it higher than the water level and have spillways around the edges at intervals. Or make one long spillway?
You mentioned earlier about 2 inch piping, so on a 12- 16 inch shelf how many lengths of pipe would be enough? I figured 2 side by side. Also how to calculate whether my pump is enough or too big?

 

[GBBUDD]

Further design answers will cost yeah

 

[GBBUDD]

i though the top step was 24"?