Some advice please :
After reading some recent postings on filtration on the Forum, I have some doubts as to whether my installation is correctly done. The pond has been running since mid July, and I am experiencing problems with water clarity. There seems to be quite a bit of suspended material in the water, but I can see the bottom. There is some of this loose floating algae in the water.
Some basic info :
Pond 15000 lt (Depth 1,300).
2 x 110mm bottom drains, leading to 800 l settlement chamber.
Pump ,35 Speck (drawing from Settlement chamber and weir).
From pump water leads to 3 bag koi sandfilter > 35w UV light > splits to 2 x 25 l Ultrazap Biofilters with Alfagrog media.
Then back to pond through 3 inlets (one approx. 350 from bottom, the other 350 from surface, and a venturi above water level).
Replaced UV globe 2 months ago.
Replaced filter sand ( 3-5mm ) 3 weeks ago.
Do water changes 2 - 3 times per week, to counter rising ammonia and nitrite levels. Backwash every 2nd day...and get my hands dirty once a week.
Aquazyme is added after every water change. Salt = 2,5%.
Stocking level : 13 koi between 40 - 80 cm and 9 of between 10 - 12cm. Will be moving some to another pond by January when I have completed my 2nd pond.
Some fish seem lethargic, and some are flashing. In the morning they seem to 'school' near the bottom inlet - facing it.

Should UV be placed after Biofilters?
Is ,35 pump good enough?
Will Zeolite in sandfilter solve some of my problems?

Any advice would be greatly appreciated.

You can place UV anywhere in the system. Mine is before the filter but if possible place it after the filter to have less restrictions and more ‘pure’ water passing it.

Buy Matala sheets. It is great and hardly any restrictions in water flow. Don’t confuse it with sponges in the way people use it in tropical tanks. It is way different and try to use the biggest pipe size you can find. Eskom is expensive so make the most of what you can change.

I used 3 x 55W UV's in a 30kL pond but switched it off afer about a year when pond settled

Hi Jack,

Your pump is too small!
This give rise to a slow water turn over of the pond water, and it is also too weak to lift the sand in the sand filter during a back wash.
I would change to a 1.1kW pump although a .75 kW should do the trick.

You are over stock, and this contributes to the poor filtration, starting with the weak pump and water turn over!

Thanks for the replies.
I incorrectly said that I have a ,35 pump, while it is in fact a ,45 Speck Magic 8. But I gather from your reply Pieter, that I would nevertheless need to install a bigger one.
Other than my stocking density, does the sequence in which I have set up my system seem OK? I am going to build another pond, which will address the stocking issue.
How would I install Matala sheets in my current setup? Vertically in settlement chamber between bottom drains' inflow and pick-up to pump. If so, how does one secure them in position? Stainless steel frame / grid?

Jack,

Quote:

How would I install Matala sheets in my current setup?

What for? There is nothing wrong with the system set up as is! Just replace the pump!

I use 2 Black Matala sheets and an Ezbio 90 pre-filter in my settlement chamber. I installed them vertical between pump and drains/skimmer and clean those 1s a week. Simply pull the sheets out and move them up and down in settlement chamber. You can pump all the dirt to waste before you fit them again. In fact I never clean the leaf basket on my main pump since it stays clean. (Use my second pump for the draining part)

You don’t need any support for the sheets, just cut them to size to fit in chamber. I was lucky since my chambers are 1.2m wide and the sheets come in 1m x 1.2m sizes.

Some people fit 40 x 40mm plastic electrical ducting on the chamber walls to slide the sheets in and out. If the chamber is deeper than the height of the sheets I would then rather use 2 x Ezbio pre-filters. (Do away with the sheets) You can remove then weekly to clean with a hosepipe.

They work great and put much less stress on the rest of your filter system. Easy to clean and very durable.

http://www.matalausa.com

Matala Ezbio Filter is also very suitable to be installed before the Sand / High Pressure system to avoid frequent clogging problem.

http://www.kingkoi.co.za/PondFilters/EZBIO.php

OK....now I'm confused!! Please bear with me as I am very new to this hobby.
I've been on the Speck website and have extracted the following:
My current pump Badu Magic 8 is appropriate for 12000 lph in a 2 bag sandfilter. They recommend this for a 30,000 - 55,000 litre pond.
The ,75 Badu Porpoise 16 pumps 20,000 lph (for a 3 bag filter) and is recommended for a 50,000 l plus pool.
Taking into consideration that I have a 15,000 l pond, my pond should be currently turning over every 75 minutes or so. Won't the bigger pump turn my pond into a washing machine?
Can't I change my mechanical filtration....Zeolite instead of sand or other mechanical media...or replace the sandfilter with a totally different mechanical filter? I see that there are many anti-sandfilter postings on the Forum.

I see you run a three bag filter. A swimming pool supplier informed me that at least a a 0,75 KW pump is needed for a three bag filter on a pool.

Jack Bach wrote:

Can't I change my mechanical filtration....Zeolite instead of sand or other mechanical media...or replace the sandfilter with a totally different mechanical filter? I see that there are many anti-sandfilter postings on the Forum.

I for one don’t use a sand filter but be wary; you are looking for trouble. The last time I crossed the SF man he he sent me this threat; “I KEEL YOU”!!!!

Jack,

Quote:

My current pump Badu Magic 8 is appropriate for 12000 lph in a 2 bag sandfilter. They recommend this for a 30,000 - 55,000 litre pond. The ,75 Badu Porpoise 16 pumps 20,000 lph (for a 3 bag filter) and is recommended for a 50,000 l plus pool. Taking into consideration that I have a 15,000 l pond, my pond should be currently turning over every 75 minutes or so. Won't the bigger pump turn my pond into a washing machine?

That calculation is without and pipe bends in any filter system, you can’t work according to that!
Anyway the more turnover gives the fish the illusion that they stay in the moving water of a river which in turns encourages growth and appetite.
Just for interest, I have a .75kW pump on my Quarantine pond of 6000lt, and a 1,1kW pump on my 10 000lt pond without any problems.

Quote:

I see that there are many anti-sandfilter postings on the Forum.

Sure there are two camps, better classified as the lazy bunch and the active bunch, and guesses who are the lazy crowd!?
Nothing clean water like a sand filter!

PS. Don’t believe everything you read or heard........................or see for that matter these days!

Jan,

You talking to me?

Just a thought, instead of replacing the pump, how about adding a pump? In such a way that either pump can operate? Then in case of a breakdown, you have a back-up.

and on the SF issue, added one to my pond, and it definitly makes a large difference.

Thanks again for the replies....I guess I go with the bigger pump...or get "keeled" and risk receiving any further advice form the expert(s)!
Pump recommendations? Speck Badu 1.1kW? Other 'good' pumps?
I see SAPlastikor in Pretoria have the ,75 @ R1249 and the 1,1 @ R1449 listed on their website. Good prices?

Jack,

Good thinking!

All my pumps are Quality Pumps, they have a bigger catch-basket then the other pumps. Some six years old and still running!

.75 kW +/- R 1000
1,1kW +/- R 1450

Now that I have a sandfilter set-up, how does one maintain it properly? I do regular normal backwashes, and some 'hand-stirring' once a week. My question : When one opens the lid, the control valve is set on backwash, switch on power, and the dirty water with muck overflows. For how long does one keep stirring - rule of thumb? Although the water becomes clearer, there are still particles of muck in it. For how long do you backwash in this mode? After sealing the lid again, do you do a 'normal' backwash and rinse.

Jack,

My rule of thumb is, they say you need to do a 10 - 15% water change every week, this therefore is the amount I backwash and rinse every week. I honeslt dont think the water will come out 100% clear unless you probably backwash the entire pond out

I backwash and rinse normally once a week and then once a month I open up the lid and backwash and rinse this way while stiring the top with a stick, do it this way since Jaco warned me of getting shocked, and I'm a big pissie when it comes to getting shocked...lol....also I dont find it necessary to backwash and rinse after you replace the lid and with the lid open I'm sure you're getting the same kind of bckwash and rinse with the lid on.

I have a 3 bag sand filter and in it 2 bags of 3-5mm koi sand with 1 bag zeolite on the top. The zeolite is light so with normal backwashes it breaks up easily inside in anycase.

This is just my process that I follow and till now which is 4 months later I have had pretty crystal clear water.