Black spots on leaves

[Fishytales]

we have black spotting on Java Fern leaves, about 10 percent of the leaves have some spotting and it looks like the older leaves. Similar spotting on anubia nana plant but only about 5 percent of the leaves. 10 crypts are all doing fine with no signs of anything wrong. The java fern and the anubia plant are still growing quite rapidly. In fact the anubia now has three flowers at this time and in 5 years, I have never had more than two flowers at one time.

I had tried the EI dosing method described by some “gurus” and did not see any great results after a year. I have since switched back to Seachem products and use the suggested dosing on this site.

The tank is 70 Gallon, substrate is 5 inches of 2 year old Fluorite red. CO2 injection is about 3 bubbles per second and I control that with a drop checker. Water changes are weekly and usually 50 %. The most recent test results are Nitrate 60ppm, Nitrite 0.00, GH about 70 ppm, KH about 120 ppm, pH of 7.2. One Tablespoon of baking soda is added at water change to compensate for low pH in local water supply.

Animal load is 30 inches, feeding is once a day and what they eat in 2 minutes is the guide for the amount fed.

Tank is fitted with a 9 Watt UV sterilizer and primary canister filter is a Hagen Fluval 305.

Lighting is now a 96 watt 50/50 combination bulb as I thought the original lighting of 2 x 96 watts was a bit excessive for my current plant load.

I have checked the Sunken Garden forum threads and have not found any ideas there.

Do you have any suggestions about the spots?

All ideas, suggestions will be appreciated.

Howard

[Tech Support AN]

I'm sorry to hear about the black spots on your plants. It seems like it could be one of two things:

1. Black Spot Algae 2. Nutrient deficiency. Now since you are dosing your tank according to the suggested dosing regime on our website, it should not be a nutrient deficiency. Especially since your Crypts, Java Fern, and Anubia plants are growing quite well.

Here is a thread that I found on Aquatic Plant Central that also addresses this same issue:

http://www.aquaticplantcentral.com/forumapc/general-aquarium-plants-discussions/62856-black-algae-spots-leaves.html

It sounds to me as if you have a really good routine going with your water changes and your feeding does not seem excessive. One thing that does stand out a bit is your nitrate level. It is a little on the high side. Have you ever checked your phosphate level by chance? Nitrates and phosphates are two of the main contributors to algae growth. What type of biological filtration do you run? In order to get those nitrates down you can boost your biological filter by adding a bacterial supplement such as our Stability. It contains the appropriate aerobic and anaerobic bacteria needed to consume ammonia, nitrite, and nitrates. If you would like to read more about Stability please follow the link below:

http://www.seachem.com/Products/product_pages/Stability.html

I would recommend continuing with your regular weekly water changes, checking your phosphate level, and boosting your biological filtration. If you have high phosphates, I would recommend using a phosphate remover like our PhosGuard. To read more about it please follow the link below:

http://www.seachem.com/Products/product_pages/PhosGuard.html

I hope this info helps and let us know if you have any further questions.

[Fishytales]

Thank you very much for your very timely review and suggestions. The Nitrate level is going down slightly with each water change since we are vacuuming a little deeper into the Fluorite and not just skimming off the top of the substrate. I am also removing some of the older leaves before they really decompose. I have ordered one of your phosphate test kits from my normal online supplier. I have never tested for phosphates before.

The biological filter is Fluval Bio-Max. I just read the instructions again and it indicated that the rings should be replaced every 6 months, and when replacing they should be replaced not all at once. The ones in the filter have been in there for at least 2 years, and maybe were in the filter at our previous residence, so I have ordered more of these.

The thread at APC was very interesting. I have posted a reply asking if anyone had success in eliminating the spots.

Thanks again for your help.

Howard

[Tech Support AN]

You are very welcome!

[Fishytales]

New similar problem -

Now all plants except our large Java Fern are doing well. The Java Fern is showing black on almost every leaf. Older leaves are showing decay, like skeletons in part are all that remain.

I have checked for comments on The Planted Tank Forum and have posted again on the the thread you folks suggested in your original reply.

The fish load has been increased to 45 inches, and I expected to see gains in the nitrogen, but in fact, it looks like I am quite deficient in it.

The most recent test results are Nitrate 15ppm, Nitrite 0.00, GH about 75 ppm, KH about 150 ppm, pH of 6.8. I am dosing based on 60 Gallons of water and following the dosing guidelines on each bottle of Seachem Fluorite, Excel. Potassium, Phosphorus, Iron and Trace. I add about 1 Tbsp of baking soda to try and get the pH at 7.2, but as you can see, I am a bit low at this time.

Using SeaChem multi-test for Phosphates, I get a reading of about 2.5. I let the test sample stay in the little tray for at least 30 minutes and do not see any changes or formation as described in the test pamphlet. Iron is so low, I cannot read anything on the SeaChem Multitest for iron.

The other two types of plants in the tank are cryptocorn wendtii and anubia nana. The anubia flowered this summer and I had 10 flowers at one time. Three was the most I have ever had before at one time in my 7 years of this hobby. The cryptocorn reproduces at a moderate pace. The leaves survive for a long time, but remain greenish and not red. Is this due to the very low iron?

Any advice, suggestions or comments will be appreciated.

Best regards,

Howard

[Tech Support EH]

Hi Fishytales! We are so sorry that this post somehow got overlooked; we are in the process of responding to your new thread. Have a great weekend!