Help With Plants In Low-End

[maurizio]

Hello all,
I didn't get any answer from the plant forum, possibly because the right place is here! I have low-end brackish (~SG 1.001, pH 8.2, KH ~9 dH, 2xT5 39W 6500K), plants (Ceratophyllum demersum and Java moss) have been acclimatized to this starting from freshwater in more than 5 weeks. Java moss just didn't make it, it's all brown with few tiny green stems reaching up towards the surface, but covered in brown. All the old ceratophyllum is dead by now (I guess I'm the first on Earth able to kill it... bought it late november), it was growing fast but the lower larger foliage was soon rotting starting from the tip of the "leaves". And by the way, I have a diatom bloom since a couple of weeks...

I got a new stem for a last attempt now, but obviously I simply threw it in, so no adaptation from fresh to brackish. Also added half dosis of a common fertilizer, hoping to help against diatoms. Pretty much same result, it grows, but the rotting process of the lower parts is faster.

Any help?



One extra thing: are Nerites ermaphrodite or not? I saw two heavily glued to each other a few minutes ago, took some pics, but not sure they were indeed mating...

 

[nmonks]

Any help?

SG 1.001 is a trivial amount of salt; not even brackish water! So I doubt salt is killing the plants. Do check the salinity. Hydrometers can be very unreliable. Start off by making some brackish water the old fashioned way: 3.5 grammes of marine salt mix in 1 litre of water should be about SG 1.001. Do this, then test with your hydrometer. Remember: hydrometers are designed to work at one specific temperature, and won't be accurate at any other temperature. Aquarium ones are usually designed to work at 25 C; check yours! Meantime, do review the plants that should work. If your plants aren't growing at SG 1.001, then something is amiss; review, and act accordingly.

One extra thing: are Nerites ermaphrodite or not? I saw two heavily glued to each other a few minutes ago, took some pics, but not sure they were indeed mating...

No, nerites are either males or females. I don't know any exceptions, though there may be.

Cheers, Neale

 

[maurizio]

Hi Neal,
thanks, I admit my hydrometer came without an indication of the calibration temperature, which is indeed an indicator of poor quality... I simply had to assume that it's 25 C, which is indeed the water temperature anyway. The water up to SG 1.001 was made in 5 weeks, by 20% water changes with 3.5 g /l of salts added. Since then, I kept adding the usual 3.5 g/l at every water change (the final goal of SG 1.002 has been postponed, given the present issue). I'll check the hydrometer; the measurement done minutes ago hardly shows SG 1.001, though. How off can it be???

Could low light be responsible? The plant is actually in a corner of the tank, not really behind the too short T5 tube.

I chose hornwort based on its declared ease of growth, I didn't even need to plant it, which allowed me to make my substrate really low end (river sand only).

I have the classic Neritina natalensis, so I believe definitely not ermaphrodite. Let's see what happens: again, if they WERE mating, it might be an indication of a higher salinity than the expected SG 1.001...?

Cheers!

 

[nmonks]

I have the classic Neritina natalensis, so I believe definitely not ermaphrodite. Let's see what happens: again, if they WERE mating, it might be an indication of a higher salinity than the expected SG 1.001...?

Mating and egg-laying happen all the time. These snails ARE freshwater snails. But the problem is that their offspring float downstream and develop in the sea.

Cheers, Neale

 

[maurizio]

I have the classic Neritina natalensis, so I believe definitely not ermaphrodite. Let's see what happens: again, if they WERE mating, it might be an indication of a higher salinity than the expected SG 1.001...?

Mating and egg-laying happen all the time. These snails ARE freshwater snails. But the problem is that their offspring float downstream and develop in the sea.

Cheers, Neale

I see, thanks. Well, I'll simply wait and see what happens with the snails. That's why we keep aquaria, after all...!

Hydrometer: well, it appears to be definitely off by a good amount, measured SG 1.006 instead of the real 1.001 at 25 C. Unfortunately, I'm PRESUMING that it's calibrated at 25 C... I checked it at a range of temperatures, from 28 down to 25 C, and the reading didn't change. It would be nice to spend some time in recalibrating it, actually... Anyhow, that means that it's overestimating, rather than the opposite, which confirms that even in the worst-case scenario, my plant problem can't be due to salinity.

Other reasons for their poor conditions could be lack of iron, insufficient light and/or photoperiod (8h with 2x39W T5 6500 K), diatoms competing (somewhere I read Ceratophyllum too goes for silicates), ... What do you think?

Thanks!

 

[iliveinazoo]

I see, thanks. Well, I'll simply wait and see what happens with the snails. That's why we keep aquaria, after all...!

Hydrometer: well, it appears to be definitely off by a good amount, measured SG 1.006 instead of the real 1.001 at 25 C. Unfortunately, I'm PRESUMING that it's calibrated at 25 C... I checked it at a range of temperatures, from 28 down to 25 C, and the reading didn't change. It would be nice to spend some time in recalibrating it, actually... Anyhow, that means that it's overestimating, rather than the opposite, which confirms that even in the worst-case scenario, my plant problem can't be due to salinity.

Other reasons for their poor conditions could be lack of iron, insufficient light and/or photoperiod (8h with 2x39W T5 6500 K), diatoms competing (somewhere I read Ceratophyllum too goes for silicates), ... What do you think?

Thanks!

if it's floating on the surface then your T5's should be producing sufficient light regardless of water volume. I'd guess that you're above SG1.002@25Deg or you're not fertilising enough.

 

[maurizio]

Thanks a lot Iliveinazoo,
the plant is anchored to the bottom (total depth is about 35 cm), and surely it's the bottom parts most affected by the problem. SG is still at about 1.001, but I never fertilized at all. I started doing it a couple of weeks ago, let's see how it goes. Hopefully...