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Whatever happened to Under Gravel Filters ?

RichardJW

RichardJW

Member
Joined
29 Oct 2013
Messages
101
Location
Shaw, Oldham
30 years ago the height of Hi-tech in a planted aquarium was to have a bed of plates under the gravel which were connected to your external filter or more usually air driven via uplifts . The theory being that like a sewage works the gravel bed acted as a huge surface area bacterial bed - the problem being in a heavy use setup ( if neglected ) it became blocked and possibly anaerobic. Move on another 10 years and we reversed the flow so it was filtered first via a canister and then passed through the gravel bed . It always worked well for me but seemed to pass into history with the advent of new generation of externals with specialised filter media . I notice that they are still available and generate controversy for reasons stated above - but, there is no mention of reversing the flow .

With all the talk of even supply of nutrients to the root zone are there any benefits to this reverse flow approach ??


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I cant ever remember UGs being part of high tech planted tanks, I can remember that 30 years ago heating cables under the gravel were essential though!
It was at one time generally believed that pulling water over plant roots would effect growth or even kill the plants but it seems this is not so!
I have often though that an under gravel style of distributing the C02 would be the best way to get an even amount of gas throughout the water column, & it has been tried by Hoppy on another form & by me on this forum but, the results were inconclusive.
I am very keen to try this again though.....
 
30 years ago don't really think anything was Hi-tech ! Doing water changes was seen as a bit radical by some .
I'm guessing for it to be useful in a planted setup a gentle movement only would suffice .
 
RichardJW said:
30 years ago don't really think anything was Hi-tech ! Doing water changes was seen as a bit radical by some .
I'm guessing for it to be useful in a planted setup a gentle movement only would suffice .
Click to expand...
Ah well there is a question! if we could feed the gas into a UGF & it effectively & equally raised up through the substrate then perhaps the high flow would still be there but in a very diffused way. we are used to blasting the contents of our tanks with high flow spray bars & the like in an attempt to get the C02 every where but, maybe a UGF would do a better job or maybe we would still have to supplement the UGF flow?
 
Have you got any pics of your latest tanks foxfish ??
I would be keen to take a look :)
You should own a masterpiece I thinks :)


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Sorry Sam, I am in the proses of a complete house renovation so all I have is 4 immersed projects , my lounge tank & a reef tank but they are in the garage just ticking over.
I have a few spectacular tanks that I maintain for private costumers but I cant really post photos of those!
However in a few weeks I will getting all my tanks back on line...
 
Interesting feedback Foxfish ! In these days of information overload everybody has access to a broad spectrum of knowledge whereas even 20 yrs ago your main source of info was LFS and local hobbyists . Interestingly , your local knowledge sources must have been more forward thinking whereas mine weren't.
I would guess on the other subject that some additional flow would be beneficial as most of the plants used probably ' appreciate a bit of movement . Just like trees need a bit of wind to encourage their root system I'm guessing a slight current would have a similar effect .
Good luck with your house renovation - you have admiration , my missus doesn't even like tradesmen around even for minor jobs . I get them done when she goes off for a week with her chums !
 
Yeah well we are pretty fed up with all the dust & tea making mate LOL
Re the flow...perhaps but the early tanks were very low flow designs & it seems to me there were far less problems 30 years ago than now..OK we couldn't grow a carpet of micro leaf plants but our tanks were full of colour & easy to keep...make you wonder sometimes!
 
Interesting you comment on the colours ! Some of the staples of the industry Tiger barbs , Rosy barbs are certainly not as big or bright as the early stock - I remember Rosy barbs the size of goldfish .The other old school staple were Swordtails and Platties ,which were a lot bigger and varied in colour variations .I think with commercial breeding the size and colour has slowly disappeared , maybe we need a bit of vigour re-introduced to breeding programmes . I already think the Neon praecox Rainbow is already a shadow of the original import .
It's interesting that various wild Angelfish are becoming available ,again whether they can be bred with some of the fancy varieties to produce quality fish would be an interesting development . Who remembers the Gold, Half-black and Black Veil-tails the size of dinner plates ?


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Remember them well , think they must've been on steroids ! Even the online resources only have them growing to 4" but I do remember having one the size and thickness of a Sharpie pen - also in many different colour ways . Don't think they'd be comparable with a planted setup though .


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RichardJW said:
With all the talk of even supply of nutrients to the root zone are there any benefits to this reverse flow approach
Click to expand...
Plants really do not care about even supply of nutrients to roots. In aquatic sediments osmotic forces, as well as Nitrogen cycle products distribute nutrients. Evenness is not relevant. Above the sediment the leaves are capable of doing the lion's share of nutrient collection and they send Oxygen down to the roots. There is plenty of movement and activity in the sediment without any need for flow supplementation. The critical area for flow is above the sediment where the leaves have limited access to nutrients and CO2. The effluent of an UG filter breaks the surface and will have the tendency to out-gas the CO2 and Oxygen.

Cheers,
 
Hi mate I am not sure what you mean by "The effluent of an UG filter breaks the surface and will have the tendency to out-gas the CO2 and Oxygen." but I assume you mean an air powered UGF?
My logic is based on a external filter powering an UGF & feeding the C02 in line, so you would get a very even distribution of the C02 rising up from the bottom?
 
Don't believe you could get a very even distribution up through the substrate for water which would be carrying the CO2,,? will alway's take the path of least resistance.
Some area's may get more than other's depending on substrate depth ,plant mass.
I once ran UG with reverse flow through small diameter grid of PVC with nearly pin hole size perforated pipe to prevent clogging.
Bottom grid resembled a hand laying on the bottom glass with finger's outstretched powered by Aquaclear power head's.
Water was then cleaned by a couple Aquaclear 110/'s.
Tank was set up for loaches ,pleco's,and worked well enough .
I can see using the return from canister to power the UG in reverse flow but think even distribution of CO2 would be difficult.
 
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