# Duckweed index ferts advice



## awtong

I have just ordered a complete TNC fertiliser to try and follow a rough duckweed style fert application as suggested by DW1305.  

Tank spec:

Juwel 450l vision with 2 x 54w T5's with reflectors 6hr photoperiod
Fluval Fx5 filter
Sand substrate with root tabs under the plants
Reasonable fish load
plants are crypts, vallis, apongeton and anubias
No CO2 enrichment
Water change is currently 25% every 2 weeks

What sort of fertlilisation regime could I use without requiring CO2 enrichment?  Should I dose the weekly amount as suggested by the bottle or start it off with a lower volume?  Is there an easy way of increasing the CEC of the substrate by adding something to it (while fully stocked) or should I just stick to adding root tabs?

If I had discovered UKAPS prior to setting this tank up I would definitely added a soil type substrate or a more nutrient rich substrate.

Thanks,

Andy


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## dw1305

Hi all,
Best of luck. 





> Is there an easy way of increasing the CEC of the substrate by adding something to it (while fully stocked) or should I just stick to adding root tabs?


 Unfortunately not easily.


> What sort of fertlilisation regime could I use without requiring CO2 enrichment? Should I dose the weekly amount as suggested by the bottle or start it off with a lower volume?


 No, just add the weekly amount as soon as the floaters start to yellow and growth slows. You can then wait until this happens again before adding the next dose etc. I'd probably buy some KNO3 and MgSO4.7H2O as well, and try these first. If you don't see any improvement in colour in about a week then add the TNC feed.

I tend to use whatever off-shelf soluble feed is remaindered, this has the advantage of being really cheap, especially for bigger tanks. The one I've got at the moment is "Gardenline Citrus feed  20:20:20" (P and K as oxides so 20:8.8:16.6 as N : P : K) + traces (N as 5NH3:5NO3:15urea), this works OK but I need to add some Mg as well. A tomato fertiliser would have been better.

I've never add any problems with ammonia toxicity with any of the fertilisers I've used, but I I have very weedy tanks, and I dose all my tanks much more leanly than you would for EI, so I get much slower growth.

cheers Darrel


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## awtong

Thanks for the reply.

So best to stick with root tabs then as I can't improve the CEC!

I have been seeing a yellowing of my giant vallis and it has stopped sending out runners and I was going to see if adding a small amount of ferts helped.  I could then tailor this to my tank as a kind of "vallis index".  This has only happened recently as it used to grow like a weed.  I think my plant mass has increased to a point that the fish waste is now insufficient.

I will have to try the all in one ferts now I have bought it but I will be very careful to make small changes.  So are you essentially using any liquid plant fertiliser for your tanks?

Somethingfishy has kindly offered me some surface plants but with a closed lid and T5 lights only a few inches from the water surface will they not become burnt to a crisp?

Andy


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## dw1305

Hi all,


> Somethingfishy has kindly offered me some surface plants but with a closed lid and T5 lights only a few inches from the water surface will they not become burnt to a crisp?


 No, should be all right. A submerged plant like _Vallis_ means that you have to factor in CO2,  and also _Vallis_ doesn't do very well in soft water, so dKH/GH may be an issue as well.

That was why I chose _Limnobium_, it doesn't seem to be effected by pH etc and shows a pretty quick response to fertilisers. 

cheers Darrel


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## awtong

Living in Newmarket near Cambridge so pretty sure it won't be a soft water problem.  It could be a CO2 issue but I wanted to try a small amount of ferts first.  I am pretty sure a liquid carbon product for a 450l tank is going to be expensive and I can't afford a gas system and I don't want a high tech tank.

I will get some floaters to try out.  This would also reduce light a little and then should lower the need for CO2 addition.

Andy


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## dw1305

Hi all,


> I will get some floaters to try out.


PM me if you can't find any, I should have some more fairly soon.

cheers Darrel


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## awtong

dw1305 said:
			
		

> Hi all,
> 
> 
> 
> I will get some floaters to try out.
> 
> 
> 
> PM me if you can't find any, I should have some more fairly soon.
> 
> cheers Darrel
Click to expand...


Thanks for the offer I will let you know if I can't get hold of any.

The other problem with going CO2 pressurised is the risk of smething going wrong.  If I gassed my pleco's I think my wife would shoot my after the time and money I have invested in them and my other fish!

Andy


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## Barbara Turner

Lol, I just seem to be getting sinkers at the minute... my Co2 running costs are lower than I was expecting. Found someone local on gumtree selling out of test fire extinguishers. 
Probably shouldn't recommend it but only £5 each and fit on to JBL reg.


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## kadoxu

awtong said:


> Thanks for the offer I will let you know if I can't get hold of any.
> 
> The other problem with going CO2 pressurised is the risk of smething going wrong.  If I gassed my pleco's I think my wife would shoot my after the time and money I have invested in them and my other fish!
> 
> Andy


Never (EVER!) adjust CO2 if you can't pay attention to your tank in the following couple of hours... make very small adjustments at a time and you shouldn't have any issues with it. The 2 times I gassed out fish, I adjusted CO2 right before leaving to work...



Barbara Turner said:


> Lol, I just seem to be getting sinkers at the minute... my Co2 running costs are lower than I was expecting. Found someone local on gumtree selling out of test fire extinguishers.
> Probably shouldn't recommend it but only £5 each and fit on to JBL reg.


I'd use them without thinking twice...


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