Plant Fertilizer over usage? Harmful to fish? Byron?

Byron

Excess nutrients in an aquarium is only asking for trouble. I can't be certain, but I would surmise that the fish deaths were the result of excess minerals. And it certainly caused the algae. And it certainly caused the plant problems you've mentioned.

Heavy metals are toxic to all organisms; iron, copper, zinc, manganese and nickel are heavy metals that are required micro nutrients for plants but when overdosed can kill plants and fish. Seachem's Flourish contains these micro-nutrients, and the website says Leaf Zone contains iron and potassium. Flourish should not be used more than twice a week in a low-tech or natural setup. I've no experience with Leaf Zone, but it is interesting that an excess of potassium has been known to cause iron deficiency in that plants cannot assimilate iron, and by adding even more the problem only worsens. Personally I would not use Leaf Zone in my aquaria.

Mention was made of the EI method. I have frequently warned of the consequences of dosing ad hoc nutrients. Tom Barr states that this method is intended for high-tech aquaria where CO2 is being added and higher light is used. The balance between nutrients and light is very important in providing the necessary micro-nutrients to benefit the plants without harming them and the fish.

I suspect your choice of light is not helping this either. Both tubes are high in the blue, but plants also require red to photosynthesize. While this might work under normal levels of nutrients, providing more nutrients than the plants can use with lighting also not providing the basics is likely to cause trouble. I would remove the actinic tube and replace it with a full spectrum that has more red than what you now have.

There is a delicate balance between light and the 17 nutrients essential to good plant growth. It is fairly easy to achieve, but care must be taken to ensure it is not upset. Deficiencies in plant growth may be the only result, but in this case it also included fish loss.

Byron.

NC Frank

With the 30 + % water change coupled with the lapse of time since it has been dosed (5 days) + the 20% water change I am doing tomorrow night I should be in the clear at this point?

Byron

Several partial water changes to dilute/remove the excess nutrients should be OK if your replacement (tap) water has a pH below 7, but if it is higher I would proceed cautiously. Ammonia changes to ammonium in acidic water, and you give the pH of the tank as 6.8. But if the partial water change results in the tank water becoming basic (alkaline) then the ammonium changes back into ammonia. In a planted tank this should not cause trouble with ammonia because the live plants are quick at using the ammonia/ammonium. You have indicated that the plants were also affected by the nutrient excess, so if this was significant and they are not growing I can't say how much of the ammonia/ammonium they might remove. Of course drastic pH swings want to be avoided, especially as the fish (and plants) are already stressed by the nutrient excess.

After five days the urgency is probably gone, and the damage has been done with respect to the plants. Some recover better than others from such things. As for the fish, let us hope that the heavy metal toxicity has not caused further internal problems that will result in health issues and possible death down the road. Fish frequently can cope temporarily with toxins but how can we know what internal damage may have resulted?

Don't expect the existing leaves on the plants to recover, but watch for new growth; if new leaves look normal, then the plant will recover. You don't mention crypts, but if you have any I would expect they have completely melted; they cannot tolerate such drastic changes. But they usually recover, so don;t disturb the roots and new leaves should grow, sometimes within days, other times within weeks. Karen Randall once wrote of crypts that recovered more than a year after they melted.

NC Frank

My changing water for the changes post over fertilization has been RO-DI water buffered to 6.8 from 7.0. I figured it would be a good time to stay away from treated tap water (especially with the major algae outbreak).

I had to trim back probably 40% of my leaves on my various plants (and there are some more that have to come out with the next round of pruning). I had some casualties but I think most will survive. I am scared about long term health issues as I have my Discus in this tank.

Thanks for the quick response. I will keep you posted on the progress.

NC Frank

I think my water is safe now after another water change. My parameters remained 0 across the board with <10 nitrates.

Total damage is 1 Platy and 2 bloodfin tetras from this tank and a dead betta from his tank.

Thankfully the other tetras and platys and all of the Discus and angels seem to be recovering nicely.