Matrix & Pond Matrix Flow Rates

[sam.bird3]

Could some one please help me.

I am going to put matrix in my sump filter but my flow rate will be close to 5000LPH (using a Eheim Compact+ 5000 Pump)
Does anyone know what the maximum efficient working flow rate is for Matrix and also pond matrix?
Also if my flow rate is higher than the maximum efficient flow rate will this be a problem? Would the Nitrates stick to the Lumps of matix if the water is flowing too fast?

Sam

[Galaxy]

Someone posted in another thread that the optimum is 700l/p but I think this is to ensure that the denitrification part of the media works. If you run the flow faster you will probably reduce the ability for it to reduce the nitrate.

[FunkyFish]

from what i remember seachem deNitrate works best at 150-200l/h... Matrix 600-800l/h and any faster use Pond Matrix. But if this is really the case, MOST external filters should be using Pond matrix.

This info was given to me by seachem when i enquired about what would be best for my filters. IF you are unsure what to use, just ask the manufacturer

[Coln]

Manufacturers flow rates for filters seem to be a bit on the wishful side, can't recall anyone
having a problem with matrix in an external with flow rate

[KMAC]

I agree with coln flow rates are generally measured with little or no media and once packed up you will find the rate is far less than originally advertised m8 i also dont think there is any difference in pond matrix from the normal matrix bar price and size

[Paul P.]

According to Seachems Matrix web page

Matrix™ may be placed in any kind of filter, and is particularly effective in a canister filter

Which would suggest that the quicker flow of canister filters (as opposed to trickle etc) benefits the media

I couldn`t find any recommended flow rates so i`m presuming that as long as the media is in contact with flowing water and you have enough of it (500 mL of Matrix™ for each 200 L of tank water and 2 Liters of Pond Matrix™ for each 200 gallons of pond water) then it should do what it says on the tin regardless of flow rates as the media works it`s main magic reducing nitrates in the macroporous surface area of the media which is situated inside the media and therefore shouldn`t be affected as much by external flow.

Having said that, presumably Pond Matrix is more suited to systems with a higher volume and/or filters with a higher turnover so in theory should do better in a sump than normal Matrix

[Graham]

I find it difficult to get my head around why flow rate would make that much difference given that the buisness end of matrix is within the micro-pores where anaerobic bacteria breaks down nitrate to release nitrogen and oxygen. At the extremes yes.

If the flow rate was ultra-ultra slow then the bacteria would be metabolising the nitrate faster than it was being supplied which would waste potential capacity and so not be as efficient as it could be. This might explain the different flow rates quoted for the two products as smaller sized media will have larger surface area to volume ratio and so more efficient for a given flow rate. If the flow rate was ultra rapid then water would flow past without much nitrate reduction but then why would this not be balanced by the more frequent passes. Possibly such a flow rate would lead to a film of still water on the surface with water gushing through the gaps but can't see it myself.

It might be that if manufacturers are suggesting flow rates by which you get the best possible reduction on one pass of the water over the matrix in which case there might be a narrow window of flow rate to aim for but given the water is being continually re-circulated and it is the long-term average reduction of nitrates we are interested in rather than the instantainious reduction then I suspect any flow rate you are likely to achieve in a sump or external filter will be in the right ball-park.

Just me thinking out loud really.

[vinboy]

I have my water bypass over two chambers of fine floss first before reaching my matrix not sure if this
improves anything but my nitrates never reach 20 before i do a water change but i am lucky to have great tap water with 3 nitrates
vinny

[Plantagenet]

It is not the flow rate that is the issue here. You need to look at the flow rate per unit area cross section of what ever the water is flowing through.

For example, 5000 litres per hour through a pipe with a diameter of 1cm would be very fast. 5000 litres per hour through pipe with a diameter of 10cm would be much slower.

[sam.bird3]

It is not the flow rate that is the issue here. You need to look at the flow rate per unit area cross section of what ever the water is flowing through.

For example, 5000 litres per hour through a pipe with a diameter of 1cm would be very fast. 5000 litres per hour through pipe with a diameter of 10cm would be much slower.

thank you. I didn't think of it like that. It is pretty obvious when you explain it like that. My pipework is 40mm so how would I work out the flow rate?

[Plantagenet]

Well i remember doing that in physics at school but i'm blowed if i can remember how to work it out now!!

An easier way to think of it would be to work out how many times over the pump would empty your sump. I would expect that the pump you are looking at will give some flow rates for pumping water up to different hights. I expect your pump will have to force the water up somewhere around 4 to 5 feet so at a guess i would have thought it would be putting out somewhere around 3500 litres an hour (you need to check this though) maybe less. If your sump is 500 litres (again you will need to work this out) then using these figures it would be emptied 7 times an hour. That means that it would take a bit of water about 8 minutes to go through your sump.

Now, i am no expert here but that doesn't sound too excessive to me. I certainly think water goes through my fluval externals faster than this.

so, how much water does your sump hold and what is the pumps flow rate at 4 feet?

[realtree]

I agree with coln flow rates are generally measured with little or no media and once packed up you will find the rate is far less than originally advertised m8 i also dont think there is any difference in pond matrix from the normal matrix bar price and size

Presuming that there is no difference between the two - is it therefore possible to use pond matrix in external filters ?? is it also then possible to break it up and reduce the pond matrix in size ??

[fridayman]

Presuming that there is no difference between the two - is it therefore possible to use pond matrix in external filters ?? is it also then possible to break it up and reduce the pond matrix in size ??

I think it would crumble a fair bit and you might get a lot of wastage.

[realtree]

Presuming that there is no difference between the two - is it therefore possible to use pond matrix in external filters ?? is it also then possible to break it up and reduce the pond matrix in size ??

I think it would crumble a fair bit and you might get a lot of wastage.

I have now seen the size of pond matrix and there is no need to reduce it in size it fits perfectly into my FX5 baskets and at half the price of normal matrix I will be giving it a try

[Galaxy]

Surely there must be a difference?