Plants Dying In Middle But Growing At Top

Hi guys

I have some really good plant growth in my new tank since I started using diy co2, but the stramge thing is that some of the plants are growing great on top but the leaves lower down have died. Now I have researched this a bit and it seems I likely have some sort of nutrient deficiency that is causing the new leaves to suck up nutrients from the older leaves. These are the tank details

Juwel Rio 180 with internal filter removed
Tetratec EX700 external filter
Hydor external heater running at about 28 degrees C
Currently have about 20 - 25 Co2 bubbles per minute being diffused into the inlet of the filter for the time being
No CO2 reading yet as my drop checker has not turned up from ebay yet
Dosing Seachem Flourish and Excel once per week as per bottle instructions
Substrate is plain old Argos playsand
PH 6.8
Yesterday I changed the standard Juwel Tubes to two 30w Arcadia Classica Daylight (apparently these are the same as the Freshwater ones)
Both the tubes have arcadia reflectors on them.

Other point to note is the tank is currently in the middle of a fishless cycle.

Here are some photos showing what I'm on about





Can anyone help me diagnose what is wrong and what I can do to fix this?

TIA

Here's a photo showing the growth at the top, which looks good to me.

How long have you had the plants?

I found that mine did this when I first got them, healthy new growth but losing old leaves. They seem to have stopped now so I put it down to them adjusting to their new water params.

Egmel said:

How long have you had the plants?

I found that mine did this when I first got them, healthy new growth but losing old leaves. They seem to have stopped now so I put it down to them adjusting to their new water params.

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I've had them around a month, so that could well be what's going on. I've just read one or two posts where people have talked about nutrient deficiency that made me concerned.

What sort of lighting have you got in your tank?? Could be that there isnt enough getting to the bottom of the plant causes them to die off at the bottom.

I would keep an eye on them, if they start to lose the new growth then yes you have a more serious problem, if however the new leaves remain healthy then I would suggest that it's just them adapting.

The other things I would add are that if you have no fish in (since you're fishless cycling) you can have the CO2 up nice and high so you're sure that there isn't a deficiency there and you may need to double check that the macro nutrients are available (Though most plants will use the ammonia as a source of nitrates anyway!). I don't know much about the seachem range but excel is just more carbon so shouldn't be necessary with a decent CO2 system and I think flourish is just trace elements. Have a look at Tropica Plant Nutrition Plus (TPN+), you can get it from aqua essentials and it contains good levels of nitrates and phosphates as well as all the trace elements.

Karl1987 said:

What sort of lighting have you got in your tank?? Could be that there isnt enough getting to the bottom of the plant causes them to die off at the bottom.

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The lighting is described in the original post, and should be sufficient. Hopefully someone will correct me if I'm wrong!

Egmel said:

I would keep an eye on them, if they start to lose the new growth then yes you have a more serious problem, if however the new leaves remain healthy then I would suggest that it's just them adapting.

The other things I would add are that if you have no fish in (since you're fishless cycling) you can have the CO2 up nice and high so you're sure that there isn't a deficiency there and you may need to double check that the macro nutrients are available (Though most plants will use the ammonia as a source of nitrates anyway!). I don't know much about the seachem range but excel is just more carbon so shouldn't be necessary with a decent CO2 system and I think flourish is just trace elements. Have a look at Tropica Plant Nutrition Plus (TPN+), you can get it from aqua essentials and it contains good levels of nitrates and phosphates as well as all the trace elements.

Click to expand...

I got the Excel to fight black brush algae in another tank, but figured it wouldn't do any harm to use in my new one too. I have looked at TPN+ before but I am considering going down the EI route once my tank has finally cycled so may revisit it then. Thanks for your comments

It might well be lack of nutrients, I'd think lack of Nitrate possibly. Also, do you have a good flow of water getting all around the tank? I'd also suggest upping your CO2 a lot. 25 bubbles per min, or 0.5bps is quite low. As there are no fish in there it doesn't matter how high you go really. Are you using pressurised CO2 or DIY/fermentation based?

DevUK said:

It might well be lack of nutrients, I'd think lack of Nitrate possibly. Also, do you have a good flow of water getting all around the tank? I'd also suggest upping your CO2 a lot. 25 bubbles per min, or 0.5bps is quite low. As there are no fish in there it doesn't matter how high you go really. Are you using pressurised CO2 or DIY/fermentation based?

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Since I started this thread I have added another DIY bottle as I am using the fermentation based method. At last count I got about 58 bubbles per minute! Nitrates were at about 5 ppm at last check, but this is going to fluctuate a lot due to the cycling.

How are you diffusing the CO2, just CO2 line into your filter inlet or have you got a glass diffuser or something?

DevUK said:

How are you diffusing the CO2, just CO2 line into your filter inlet or have you got a glass diffuser or something?

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The Co2 line goes into the bottom of the filter inlet and the bubbles pass up the tube and dissappear into the filter. Every now and again a load of bubbles shoot out of the filter outlet with an annoying squeaking sound, so I may get a diffuser instead soon. My other half said she thought there was a bird trapped somewhere yesterday

Definately worth getting a diffuser Nano diffusers can be bought for not much on eBay, or Aquaessentials do a nice range

DevUK said:

Definately worth getting a diffuser Nano diffusers can be bought for not much on eBay, or Aquaessentials do a nice range

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There seems to be a lot of choice of types and brands. Any suggestions of what to go for?