New aquarium, plants won't grow? Help!

[Scott]

Hi everyone!
This is my first post on this forum so forgive me if I've screwed anything up.

I've had my new aquarium for 4 months, it's a 240 litre upgrade from my previous 130. (Previous tank was internally filtered, 2 x T8 lit, gravel substrate, overstocked, planted and sporadically dosed with EI dosing) my plants did very well indeed. The new aquarium is supposed to be an all round improvement in all aspects but my plants just are not growing. I've transferred a Cryptocoryne and Vallisneria offshoot from the old tank both which previously grew fast and lush, some unknown plants from my lfs and ordered some low tech plants from aquaessentials including Ludwigia Repens, Water Wisteria, Lobelia Cardinalis and Staurogyne Repens.

The Wisteria initially grew a bit leggy and the lower leaves died back so I trimmed it and replanted not it's not growing at all and even melting. The Ludwigia hasn't moved, the leaves have curled and grown algae and the worst ones I trimmed off. The Crypt has only produced 1 new leaf in 4 months, the Val hasn't done anything. The Staurogynes top leaves have disintegrated and looks like it's trying to grow new shoots lower down. Of the unknown lfs plants I got 3 melted away and the remaining 2 have not grown one bit.

My new tank is 240 litre
2 x 20W LED floodlights (8 hour photoperiod)
Fluval 306 canister filter with Biohome plus media
1600lph circulation pump
Manado substrate
EI dosing KH2PO4, MgSO4 and chelated trace Fe, Mn, Zn, B, Cu, Mo. Flourish Excel.
Fish: 2 large Plecos (plus about 25 tiny offspring) 1 large clown loach, 6 Danios, 6 Tetras, 4 guppys, one Otto, 3 amano shrimp and a colony of cherry shrimp. Oh and 1 Nerite snail
Weekly 50% water change

I don't have any test kits but I don't see why I should really need to get any at this point when I just want some basic plant growth.
I have some theories as to my problem, firstly is this Calcium deficiency? Secondly is the Manado substrate with it's CEC stripping my fertilisers out of the water column? Lastly is the Biohome filter media stripping too much nitrate out of the water?

Help!
Thanks in advance for any advice!

I'll try and add some pics here:

 

[techfool]

You have got an algae problem. I don't think plants can grow when the life is being sucked out of them by algae. It varies by tank but what worked for me is reducing light (because I don't dose CO2), increasing liquid carbon, decreasing ferts (because I'm lazy with water changes) and increasing flow. Increasing flow saved my crypt that was getting clogged up with all kinds of rubbish. I've just had to divide it, it was getting so big. It can also take a while for plants to take off. They can just sit there doing nothing for weeks. But now even my anubias is out of control.
What works to control algae depends on your aquarium but I feel that as a general principle, the more light you have the more trouble you need to take so I would look at that first.

 

[Franks]

That’s far too much light with zero Co2 injection. Even with Co2 injection, you’d probably be in the realms of lethal livestock levels in order to satisfy your relatively low plant mass.

I’d reduce light to T8 level and start at a 6 hour photoperiod once you’ve removed all the algae.

(Or one floodlight raised high above the water level for 6 hours per day)


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[X3NiTH]

Hi there welcome to UKAPS.

Too much light is the first problem, the second problem is you don't appear to be adding any nitrate to the tank (are you adding it and forgot to list it, I don't know if there is any in your tap, what does your local water report for your area say), If you are relying on the fish to provide it, it may not be enough as there is far more dilution now in the new tank than your previous tank for the same amount of fish.

Problem number three is a bit more complicated, You appear to be living in a hard to very hard water area (I checked Dorset area, it's about GH of 15, KH is higher still), this may not play well with your chelated Fe trace (I'm presuming EDTA), you are not adding any supplemental CO₂ so the likelihood is that your tank waters pH is going to be above 7.5 (or higher) pretty much all the time, at this pH Fe EDTA is unstable and will unchelate making the free iron in the tank to become unavailable to the plants, thus it will make that unbound EDTA available to be bound to other nutrients, your sporadic dose of Fe may be gone that next day to the pH alone (all the other trace elements stay bound to EDTA up to pH 10).

For higher pH water you can add the iron with a different chelate like Fe DTPA so that it sticks around for a little longer.

 

[Scott]

Thanks for the replies guys, it was initially my intention to put a lot of plants in the tank in the first instance to outcompete algae growth. That idea went the opposite way. I had new tank/diatoms affecting the plants for the first few weeks, it was downhill from there.

I've looked up water parameters for my area:



Your absolutely right about the hardness and pH issues, I'm using ferts I purchased from Aquarium Plant Food UK and no I'm not dosing any addition nitrates, only what's in the tap water and what the fish produce.

 

[Franks]

Ferts and water hardness equate to such a small percentage of the main issue here which is your insane amount of light and zero Co2 injection.

By reducing your light intensity you will instantly give the plants a better chance to establish but first you need to remove all the algae. Its won this battle.

Look at why your previous setup was so successful. You had a huge bioload fertising your water column and you had a much more appropriate light setup with what sounds like an abundance of plants too.

Ferts and water hardness are not the issue here.

 

[ian_m]

Low Nitrate levels can cause algae. Ignore your water report, that is for the water companies test point on a particular day, not your tap water today.

So add nitrate, even in excess as this will help reduce algae, along with shorter and not so bright lights. Excess's phosphate, or even spot dosing phosphate and/nitrate on bad algae patches will help. You will need nitrate levels in 1000's ppm before it becomes a livestock issue.

If you have no livestock I would dose a x10 liquid carbon (Flourish Excel) to wipe out the algae. Might damage plants. Or 3-4 day 100% blackout will also work.

 

[Scott]

Since writing my last post I have taken delivery and dosed some potassium nitrate and have obscured the main glare of my LED floodlights with some masking tape, I have to say all plants in my aquarium have put out promising new growth, including the ludwigia. I will update this thread with my aquariums progress.

Thank you all for your suggestions!

 

[HiNtZ]

Sorry but am I the only one here that thinks 40W over a 240 is minimal? Even if they are LEDs - that's not high light by any means. I ran 60W floodlights on my 155 with great results and just liquid carbo. Half of those LED floodlights don't even live up to the specs - take at least 20% off and you're left with average lighting for a tank that size.

Of course, there are other problems at play here, but I'm willing to bet the light isn't the culprit.