[Wet Thumb Forum]-Salinity Build-up and Poor Plant Growth

[dwalstad]

With my new conductivity meter, I can report a salt build-up in my tanks, which don't get many water changes.

I measured over 1,000 microsiemens in my 50 gal which hasn't had water changes in about 6 months. The salinity is 3 x that of my tapwater, which is 300 microsiemens.

The water hardness didn't increase that much (GH of 17 versus tapwater with GH of 13).

When I changed much of the water in another tank (my 45 gal), the Water Sprite, which was pale and dying, turned green and started growing again.

I suspect that salinity may build up in tanks over time and may slow the growth of salt-sensitive plants.

Just another factor in keeping aquarium plants!

[dwalstad]

With my new conductivity meter, I can report a salt build-up in my tanks, which don't get many water changes.

I measured over 1,000 microsiemens in my 50 gal which hasn't had water changes in about 6 months. The salinity is 3 x that of my tapwater, which is 300 microsiemens.

The water hardness didn't increase that much (GH of 17 versus tapwater with GH of 13).

When I changed much of the water in another tank (my 45 gal), the Water Sprite, which was pale and dying, turned green and started growing again.

I suspect that salinity may build up in tanks over time and may slow the growth of salt-sensitive plants.

Just another factor in keeping aquarium plants!

[aquabillpers]

I once sold Water Sprite to a local fish store,
but if it didn't sell in a few days it would die. Even plants placed outside in the sun would still die.

It turned out that the proprietor added sodium chloride to his central water system, to keep his fish healthy, he said. He also commented that he just couldn't keep plants alive, and as a result he didn't carry them.

I think a lot of people who add salt to their tanks as a prophylactic overlook the build-up problem, as do those with ion exchange water softeners. Minerals don't evaporate.

Bill

[aquabillpers]

I once sold Water Sprite to a local fish store, but if it didn't sell in a few days it would die. Even plants placed outside in the sun would still die.

It turned out that the proprietor added sodium chloride to his central water system, to keep his fish healthy, he said. He also commented that he just couldn't keep plants alive, and as a result he didn't carry them.

I think a lot of people who add salt to their tanks as a prophylactic overlook the build-up problem, as do those with ion exchange water softeners. Those who just add water to replace evaporated water also can have a problem. Minerals don't evaporate.

Bill

[aviel]

Diana,

Some hobbyists are adding 1 table spoon per 5 gallons. I would like to know if this number is way higher than the salinity that you measured, or quite the same or negligible.

Also which plants are more sensitive to salinity? And generally why high salinity is bad for plants.

Aviel.

[DataGuru]

Yes, could you convert that to parts per thousand (% solution?

[aviel]

0.1 % = 0.75 teaspoon per gallon so I have googled...

So I am talking about one table spoon (=~ 3 tsp) per 5 gallon -

That's about 0.08% salinity,

Aviel.

[dwalstad]

Salinity is hard on all plants, including terrestrials. Just ask irrigation farmers in desert areas (salt build-up in the soil eventually slows crop growth).

I think that the high salt concentration stresses the plant via ordinary "osmotic stress". Plants that are adapted to high salt do okay; those from softwater areas are injured by the osmotic stess.

Aquatic plants (like Bacapoa monnieri) that have evolved in brackish water are known to be salt tolerant. One experimental study showed that this species can tolerate even 0.5% NaCl quite well.

Within the next couple weeks, I'll make some standardized NaCl solutions, measure them for conductivity, and report back.