- My Forums
- Tiger Rant
- LSU Recruiting
- SEC Rant
- Saints Talk
- Pelicans Talk
- More Sports Board
- Winter Olympics
- Fantasy Sports
- Golf Board
- Soccer Board
- O-T Lounge
- Tech Board
- Home/Garden Board
- Outdoor Board
- Health/Fitness Board
- Movie/TV Board
- Book Board
- Music Board
- Political Talk
- Money Talk
- Fark Board
- Gaming Board
- Travel Board
- Food/Drink Board
- Ticket Exchange
- TD Help Board
Customize My Forums- View All Forums
- Show Left Links
- Topic Sort Options
- Trending Topics
- Recent Topics
- Active Topics
Started By
Message
Water Salinity Measurement
Posted on 2/12/26 at 11:42 pm
Posted on 2/12/26 at 11:42 pm
I am interested in checking the salinity of a brackish marsh over time. Has anyone on the board ever used a handheld salinity meter to do such a thing?
How did it work?
What kind is best?
To get right to the point…how much salinity can marsh plants that ducks eat tolerate?
How did it work?
What kind is best?
To get right to the point…how much salinity can marsh plants that ducks eat tolerate?
This post was edited on 2/13/26 at 1:21 am
7
Posted on 2/13/26 at 7:21 am to Spankum
Posted on 2/13/26 at 7:25 am to Spankum
get a refractometer marketed to aquarium keepers for about 30 bucks
I have kept a 180gal brackish tank for about 30 years and tried to keep just about every plant and fish from coastal Louisiana
most "fresh water" plants can survive in a specific gravity up to about 1.005, some up to 1.008-1.010, permanently.
I keep my tank at 1.005-1.008, and have a healthy mix of mostly native fresh/ brackish /marine fish with some exotic and native freshwater plants. Full marine is about 1.025
I have kept a 180gal brackish tank for about 30 years and tried to keep just about every plant and fish from coastal Louisiana
most "fresh water" plants can survive in a specific gravity up to about 1.005, some up to 1.008-1.010, permanently.
I keep my tank at 1.005-1.008, and have a healthy mix of mostly native fresh/ brackish /marine fish with some exotic and native freshwater plants. Full marine is about 1.025
This post was edited on 2/13/26 at 7:27 am
Posted on 2/13/26 at 9:04 am to Spankum
Natural and cultivated populations of widgeon grass are found along the Atlantic and Pacific coasts and in wetlands throughout the Midwestern and Western states. They grow in alkaline, brackish or saline waters between 2 and 19 ppt.
Typical of what we see in SW La excluding extreme drought years on salinity.
Typical of what we see in SW La excluding extreme drought years on salinity.
Posted on 2/13/26 at 10:41 am to luvdoc
quote:
I keep my tank at 1.005-1.008, and have a healthy mix of mostly native fresh/ brackish /marine fish with some exotic and native freshwater plants. Full marine is about 1.025
Now you have my attention. What size tank you running and what kind of fish? Would be cool to have reds, bass and sheepshead in the same tank.
I thought about doing a big saltwater and make me something that looks like the bottom of a oil platform for structure and decor.
Posted on 2/13/26 at 10:47 am to tigerbait703
That's awesome. Have you noticed whether it's possible for the redfish and drum to reproduce in this situation? I remember an experiment years ago where they stocked redfish in freshwater lakes in West Texas (San Angelo to be exact). The redfish thrived and grew, but they would not reproduce. Was wondering if it was possible in a brackish water enviornment.
Posted on 2/13/26 at 11:40 am to tigerbait703
not to hijack this thread too much, but even at 180 gal, my tank is far too small for all of the fish varieties you describe.
This post was edited on 2/13/26 at 12:29 pm
Posted on 2/13/26 at 12:13 pm to KemoSabe65
Thanks…there is a lot of great info in this thread! I would like to target seeding grasses (for dabbling ducks) instead of tubers which attracts divers.
It looks like I need to target 5 - 25 PPT salinity. I think I can manage it to substantially that level outside of something like hurricanes, when the ecosystem goes haywire for several years.
It looks like the refractometer-type instrument is the simplest and cheapest…but I don’t know if they work in that crappy water (muddy and loaded with plant matter).
Also, I don’t know if a surface sample is sufficient or if you need a sample somewhere else in the water column,
It looks like I need to target 5 - 25 PPT salinity. I think I can manage it to substantially that level outside of something like hurricanes, when the ecosystem goes haywire for several years.
It looks like the refractometer-type instrument is the simplest and cheapest…but I don’t know if they work in that crappy water (muddy and loaded with plant matter).
Also, I don’t know if a surface sample is sufficient or if you need a sample somewhere else in the water column,
Posted on 2/13/26 at 12:28 pm to Spankum
(no message)
This post was edited on 2/13/26 at 12:29 pm
Posted on 2/13/26 at 12:41 pm to Spankum
the salinity should be uniform independent of Depth. murky water should not prevent accurate use of the refractometer
This post was edited on 2/13/26 at 12:42 pm
Posted on 2/13/26 at 1:03 pm to luvdoc
Posted on 2/13/26 at 2:42 pm to Spankum
Use this on my tank-- milwakee refracto Accurate and easy to use.
I have an 8' long 300 gallon which is way too small for a red or sheepshead. They would need a massive tank. Custom large cylinder tank would be ideal.
I have an 8' long 300 gallon which is way too small for a red or sheepshead. They would need a massive tank. Custom large cylinder tank would be ideal.
Posted on 2/13/26 at 2:51 pm to Spankum
If it’s in Louisiana the ldwf may have a sight close by that they are checking monthly. Call local ldwf fisheries biologist and strike up a conversation.
Posted on 2/13/26 at 3:11 pm to luvdoc
quote:
the salinity should be uniform independent of Depth. murky water should not prevent accurate use of the refractometer
Thanks!
Posted on 2/13/26 at 4:24 pm to Wolfmanjack
quote:
If it’s in Louisiana the ldwf may have a sight close by that they are checking monthly. Call local ldwf fisheries biologist and strike up a conversation.
Either this or CRMS. There are monitors all across the coastal region as part of that program.
If it's truly a brackish marsh, then salinity isn't likely to be an issue for the vegetation you're looking to manage for because of the wide range in salinity tolerance those species have. Water depth would be what I would be more concerned about.
General rule(s) of thumb when it comes to marsh types: Fresh marshes are typically the most diverse, and composed of plants that can tolerate wider ranges in flooding, but the least salt tolerance; brackish has widest tolerance for both salinity and depth, but depends on species; and salt marsh is least diverse and most tolerant of salinity, typically least tolerant of prolonged, deep water (since these are typically strongly tidal).
Just based on my observations from years working and planting in the marsh.
Posted on 2/14/26 at 1:54 am to Cowboyfan89
I have been hunting this marsh since the mid 70’s. I’ve seen it go from nearly fresh water where the vegetation was so thick we had to use go-devils to get to the blinds to the other extreme of vast stretches of open water where we could actually catch crabs around the landing. The marsh has stayed a constant 2-3 ft deep all of this time.
My goal would be when there is a large swing in salinity, I want to find out why it happened so we can react relatively quickly. I don’t want to start brushing blind and find that some levee has blown out and all of the vegetation is dead in the marsh.
You say that you have planted in the marsh…I did not know thst we}as possible. Do you just scatter a bunch of seeds or what? I am very interested in this!
My goal would be when there is a large swing in salinity, I want to find out why it happened so we can react relatively quickly. I don’t want to start brushing blind and find that some levee has blown out and all of the vegetation is dead in the marsh.
You say that you have planted in the marsh…I did not know thst we}as possible. Do you just scatter a bunch of seeds or what? I am very interested in this!
Posted on 2/14/26 at 6:59 am to Spankum
Submerged aquatic vegetation is a fickle bitch. A wide range of environmental conditions will deflate your duck season in a heartbeat. It’s kind of like those crawfish prices… too much rain, too little rain, strong south winds, strong north winds, hurricanes etc can and will have a detrimental effect on your season. A levee around your marsh with water control structures in place would help mitigate said environmental conditions possibly but good luck with that. I’ve pondered this planting of submerged aquatic vegetation in the past and could not find anyone who had been successful or even attempted it in a brackish marsh. The other guy is likely talking about planting marsh grasses to stabilize and preserve the land in the marsh.
Posted on 2/14/26 at 7:42 am to Spankum
Spank, imo what you want to accomplish in your marsh is going to cost a ton of money. Golf courses and marshes have a lot in common as they both need intensive management to be productive. Theres not much you can do unless you have a landman, plenty of time and an unlimited budget.
Posted on 2/14/26 at 8:21 am to Dulacrat
quote:
That's awesome. Have you noticed whether it's possible for the redfish and drum to reproduce in this situation?
They won’t spawn in landlocked areas. Needs to be tidal
Posted on 2/14/26 at 7:41 pm to Spankum
quote:
You say that you have planted in the marsh…I did not know thst we}as possible. Do you just scatter a bunch of seeds or what? I am very interested in this!
Wolfman is correct in his assumption--I'm speaking specifically of grasses/rushes like smooth cord, marshay, cutgrass, bulrush, etc.
In other words, common and easily grown species. Species like widgeongrass would likely be very difficult to propagate effectively because of the relatively narrow salinity range it tolerates (up to 10 ppt) and need for sunlight, which isn't solely dependent on depth. Widgeon grass can grow in up to 3 ft of water, but that's going to be water that doesn't have a lot of suspended sediment (i.e., not much flow).
quote:
I’ve seen it go from nearly fresh water where the vegetation was so thick we had to use go-devils to get to the blinds to the other extreme of vast stretches of open water where we could actually catch crabs around the landing. The marsh has stayed a constant 2-3 ft deep all of this time.
What has caused the open water? The fact that you went from thick vegetation to open water but still have the same depth is interesting, (and not very common, unless that bottom is very hard).
quote:
My goal would be when there is a large swing in salinity, I want to find out why it happened so we can react relatively quickly.
I take it this is in a location that is relatively protected from saltwater unless something like a levee fails? Otherwise, this is difficult if you're in a naturally tidal system, or one that doesn't have significant freshwater input outside of rainfall. And at 2 to 3 feet deep, any prolonged drought is going to lead to an increase in salinity since water evaporates but salt doesnt.
Ive had project locations in South Louisiana where salinity spiked from 10-15 ppt to over 32 ppt in droughts. Not much you can do about that unless you can somehow pump water in.
Page 1 of 1
Popular
Back to top
Follow TigerDroppings for LSU Football News