Weak & Stunted Plant Growth

[Coys]

I have a 240 liter aquarium populated with tetras (Congo, Emperor and Cardinal). I replace 50 litres per week with RO (my local water supply is horribly alkaline) and supplement with Seachem Equilibrium, Alkaline Buffer and Acid Buffer. At present the pH is around 6.8, KH 3 and GH 7, Nitrate 20-30, Ammonia and Nitrite both 0, although I have to admit that I was negligent on the GH and KH for a while and let the KH slip to 0 probably for some weeks before I noticed (I know...) and began buffering with the Seachem products. I also dose every 1-2 days with 5ml of Seachem Flourish Excel.

The set up has been running for 10 months or so and at first the plants were thriving, especially the Amazon Swords, which were constantly sending out new leaves bigger than the old ones, and the Vallis, which quickly reached the top of the wqater and sent out so many runners that I was pulling it up in handfulls.

However, over the last 6-8 weeks the Vallis has almost died off and the swords have developed stunted, yelowish and in some cases twisted/deformed new leaves with translucent patches (see photo).

I should also mention that I did supplement with root tabs around the swords about 6-8 months ago and added some new ones yesterday in case the roots were being starved of nutrients, which I doubt given the amount of stuff that comes out of the gravel if I stick the syphon in deep during the weekly clean up.

So, any ideas what could be causing (a) the Vallis die off (maybe the Flourish excel and/or lowish pH) and (b) the stunted, yellow, twisted, translucent Amazon Sword new leaves (possibly a lack of Calcium before I started buffering and/or other minerals such as iron, potassium)?

 

[dw1305]

Hi all,

Alkaline Buffer and Acid Buffer

You don't need either of these, you can just add a small amount of tap water to raise your dKH & dGH. If you buy a conductivity meter you can use this to give you a measure of how much tap water to add to your RO. You will need to find your own "sweet spot", but about 200 microS would be a place to start.

I'm not a liquid carbon user, but I've never had much joy with Vallisneria in rain-water, it does well in out tap water low tec. water is about 17dKH and very low in nutrients.

which I doubt given the amount of stuff that comes out of the gravel if I stick the syphon in deep during the weekly clean up.

I think this might be your problem, you don't need to vacuum your gravel if you have plants.

Because the new leaves on your Swords are effected, it is a deficiency of a non-mobile element. Nitrogen (N), Potassium (K) and Magnesium (Mg) deficiencies all cause yellow leaves, but are mobile elements within the plant, and would effect older leaves.

Calcium isn't mobile, but doesn't usually cause yellowing, symptoms are leaf edge necrosis and twisting.

Usually 99% of the iron deficiencies people diagnose aren't iron, but in this case the most likely deficiency really is iron (Fe). I'd add some chelated iron, FeEDTA would do.

Most iron becomes available to the plant in reducing zones in the substrate. By vacuming your gravel, you will have reduced the possibility of this happening.

cheers Darrel

 

[Coys]

Hi Darrel,
Thanks for you reply; I really appreciate your comments and advice.

I did try mixing RO and tap 50/50 initially, but the very high pH of the (Essex) tap water stopped me reaching my target pH, so I switched to 100% RO and, once I realized that the KH had collapsed, I started buffering. I'm not too sure about the liquid carbon either, but I'm switching to Co2 injection soon, which I hope will help.

I may have misled you on the gravel vacuuming; I normally only vacuum the debris on the surface of the gravel, but if I do stick the siphon deep into it (which I did last week in one spot for a test) then it is shows that there are plenty of nutrients in there, so I don't think that's the issue.

So you think that it's probably not calcium (do you think that my present GH and KH levels are sufficient?), but an iron deficiency? If I address the deficiency would you expect the plants pick up with new growth or is it best to replace the worst affected ones?

FWIW the Crypts (Balansea and Wendtii) and thriving, as are all of the fish...

Steve.

 

[dw1305]

Hi all,

I did try mixing RO and tap 50/50 initially, but the very high pH of the (Essex) tap water stopped me reaching my target pH

It is probably best to just ignore pH, it isn't a very useful measurement in <"low conductivity water">. Your tap water will probably come out of the tap at 700 microS and pH8.

The problem with pH is that it isn't a straight forward measurement, and often people understandably extrapolate from

You probably only need to add about 10% Essex tap to give you enough dGH/dKH (Ca++ and HCO3- ions). Because of <"your geographical location"> it is unlikely that your tap water contains much magnesium (Mg++), because the water will come from a chalk aquifer. If you don't add any extra magnesium it might be worth adding some (via <"Epsom Salts">).

If I address the iron deficiency would you expect the plants pick up with new growth or is it best to replace the worst affected ones?

The new leaves the plants grow should be normally green and healthy, the yellow leaves won't ever recover, because the deficiency isn't of a mobile element.

FeEDTA should be all right but other chelates are better at higher pH values.

cheers Darrel

 

[dw1305]

Hi all,
I don't know quite what happened there, it should have said:

The problem with pH is that it isn't a straight forward measurement, and often people understandably extrapolate from hard water, where changes in pH reflect large changes to water chemistry, to soft water where pH can never be stable and small changes in water chemistry cause large changes in pH

cheers Darrel

 

[Coys]

Thanks for the advice Darrel. I've been dosing with Flourish Iron for four days now and I'll report back in a week or two with the results.

 

[Coys]

Well, it's been 3 weeks of dosing daily with Seachem Iron and 2-3x weekly with Seachem Flourish and the plants appear to be back to normal. Two of the swords have developed flower stalks and new leaves are longer, untwisted and without brown patches.

 

[Jaap]

Vallis definitely don't like Flourish Excel!

 

[Coys]

Vallis definitely don't like Flourish Excel!

Flourish, not Flourish Excel.

It's confusing, but they are two completely different products, the first being trace elements and micro nutrients and the second being Vallis-melting liquid carbon.

 

[Jaap]

So, any ideas what could be causing (a) the Vallis die off (maybe the Flourish excel and/or lowish pH) and (b) the stunted, yellow, twisted, translucent Amazon Sword new leaves (possibly a lack of Calcium before I started buffering and/or other minerals such as iron, potassium)?

Ok sorry, you said Flourish Excel in this post and I thought I should let you know...

 

[Coys]

Ok sorry, you said Flourish Excel in this post and I thought I should let you know...

Yes, you are correct; I did mention it in the first post in the thread. I know that a lot of people believe that Excel melts Vallis (and FWIW, from experience I think they are probably right!), although others dispute that. I am still using Excel until I install a Co2 system though and have given up trying to grow Vallis for the time being. The other plants are recovering nicely now though.