Blue Spring is a first magnitude spring, which means it discharges more than 100 cubic feet per second or about 650,000 gallons a day. Average discharge based on available records is 126 cubic feet per second. Discharge has been measured at over 125 million gallons a day in the past. In times of drought, the spring is known to still discharge about 10 million gallons a day. Most of the other springs are what cave divers consider low flow systems. At times, Hole in the Wall is even known to siphon.

The average water temperature in the springs is 68 degrees year round. The water around the Blue Spring basin tends to stay this temperature year round as well because of the amount of water being discharged every day. The temperature of the pond fluctuates throughout the year from about 51 degrees in the winter to 88 degrees in the summer. During most winters the water temperature in Hole in the Wall and Twin will drop slightly. The water temperature in Hole in the Wall has been recorded as low as 56 degrees and in Twin as low as 65 degrees.

The water discharging from Blue Spring is believed to have been under ground for about 17 years. So the chemical composition of the discharge water is a result of rain falls and seepage from 17 years ago. The state has seen an increase in nitrates in the discharge water. This is due to the large focus on agriculture in Jackson County. What we’re seeing in this is what agriculture was doing almost 2 decades ago. Rain falls and seepage today will not be seen for another 17 years. This makes it extremely important to protect our ground water today because we will not see the effects of what we dump on the ground for another 2 decades.

Merritt’s Mill Pond flows into Spring creek, which starts just south of the dam on Hwy 90. Spring Creek continues for another 2.5 miles before it joins the Chipola River. The pond has existed in its current length since about 1866 when a dam was built at the present site. A year or two later the dam was sold and enlarged, creating the size of the pond as we see it today. The first dam was built at Blue Spring during the 1830s. It was too close to the spring and didn’t allow for the wheel to turn (it was a grist mill) so it was taken down. In the 1840s, a second dam was built about 2.5 miles down from the head spring. When the final location of the dam was established in 1866, there was a lawsuit by the owner of the existing dam because the new level of the pond stopped his mill from working. Even before the first dam was built, the creek that ran from Blue Spring to the Chipola River was large enough that the native Americans that lived in the area could travel on it by canoe.

Over it’s history, Merritt’s Mill Pond has been drawn down 6 times. The first draw down was in 1956, then in 1971-72, then 1980, 1990, 1994-96, and the current draw down of 2012. The draw down in the 1990s was done to make some modifications to the dam. All other draw downs occurred to try to improve the health of the pond.

Today, Merritt’s Mill Pond is very popular for cave diving, fishing, and general recreational aquatic activities. The Blue Spring Recreational Area park has been know to have several hundred people present on hot summer days. The park operates 7 days a week during the summer months with Memorial Day Weekend as its first weekend being open to the public and Labor Day weekend as its last weekend being open to the public. Hours are from 10-6 Monday through Saturday and 11-5 on Sundays. The county provide lifeguards and a concession stand during those hours. The pond is very busy most summer days with several pontoons, fishing boats, and personal water crafts running up and down the pond. During colder months you can still find the dedicated person out there fishing as the pond is known for record catches.

Cave diving is popular on the pond year round. Up until 2008 cave diving was restricted at Blue Spring during the hours it was open to the public in the summer. The county lifted that rule and opened the park to cave divers 24/7. In 2010 they placed key pad on the gate so visitors just have to enter the key code to open the gate. Access is $25 per day or $150 per year. Or you can access the spring, as well as the other 7 springs by boat by using one of the boat launches along the pond.

The pond has 3 boat launches along its length. Baptism Launch is the one closest to the head spring and is located at the end of Day Loop Rd, just before the entrance to Blue Spring park. Baptism Launch is a primitive launch and does not allow for launching trailered boats. Hunter Fish Camp Launch is located about 3 miles south of Baptism Launch, right across from Gator Hole. It is a paved launch. Be careful though! When the water level is about a foot low your motor prop will hit the bottom so keep it up. The third launch is located at Arrowhead Campground which is right at the dam. There’s a small fee to launch a boat from this ramp.

If you’re interested in taking a tour of the pond or doing some guided cave dives contact us at chipoladivers@gmail.com or call us at 850-594-7991. We have a 24 foot pontoon boat and a 16 foot wide jon boat that will get us around the pond quite easily.

Scientific interest in the spring first arose in the mid 19th century when mastodon bones were reportedly first seen. Since that time the remains of several extinct mammals that date back to the last glacial period have been found. The Florida Geological Survey (FGS) commissioned their first study of the spring in 1930 and has conducted several other studies since that time.

Wakulla Springs ranges in the 200-300 foot depth range and is the longest cave system in Florida measuring at over 28 miles. Some cave divers believe there are more passages to be explored and that the system eventually empties into the Appalachicola River. Two groups of cave divers have had scientific permit access to Wakulla Springs over the years. One group continues to conduct studies in the system. Opening Wakulla Springs to limited cave diving without scientific permit could help produce more information on the system and possibly expand the system beyond its currently known boundaries.

While the Florida DEP will continue to look into the proposal to open Wakulla Springs to limited cave diving, it is just a small first step in the process. There is no timeline in place and this does not guarantee any changes. However, this first step is a small victory of cave divers. Thank you for your support and please keep checking back here. We will continue to post updates and requests for more letters when needed.

See an article in the Tallahassee Democrat here – DEP to draft plan for diving at spring

The draw down began January 23, 2012 and continued for the next five days dropping the water level three feet. The purpose was to expose the vegetation to the air and hopefully get some freezing temperatures to kill it off. The state was also planning on spraying the pond with a chemical safe for swimmers and fish but deadly to the vegetation.

Here are some photos from the draw down.

Merritt’s Mill Pond during the draw down

Jackson Blue Spring before and after photos

The original Armadillo sidemount rig, in my opinion, is the best commercial sidemount rig available. It is simple, low profiled, streamlined, and robust. It is also the only sidemount rig I’ve seen that has not, or would not, require any modifications for it to work for me.

The Armadillo comes with the inflator hose already coming off the bottom of the wing and the dump on the top. It was like that when they were first introduced to the market in 2002 and continue to be sold that way today. The Armadillo also comes with adjustable shoulder straps. They can be located anywhere on the waist strap that works for the diver. They are a simple, single piece webbing with no padding. The material used is heavy duty and robust. The rig is reinforced with heavy duty 2-inch webbing along the center and butt plate. The bars used on the butt plate are curved rather than squared. I thought this might be an issue when I first got it because I was in the habit of “locking” my snap bolts along the top of the bars. This hasn’t been an issue with the Armadillo. I still pull my cylinders up toward my shoulders and they stay where I want them just fine.

Even though the rig I bought was used there were no modifications made to it by the previous owners. I have made a total of two modifications to my Armadillo. I added a chest strap, which I only need when I’m carrying stages (most dives), and I fixed the pull dump to the shoulder harness a little more permanently than how it’s shown in the owner’s manual.

The Armadillo does have some drawbacks. The lift is only 33 pounds. So I’m still using my Nomad for my trimix dives because my trimix cylinders are 108s and 121s. My Nomad barely has enough lift for those. The Armadillo definitely doesn’t have the lift for those. That being said, I have been able to dive my Armadillo with 2 Faber LP95s, 2 AL80 stage cylinders, and an AL40 deco cylinder. The other drawback is I can’t use it as a backmount rig so when I’m teaching students in backmount I have to use my Nomad. I suppose I could drill some holes in the center of the back to accommodate backmount but I don’t really see a need for it. Other than that I haven’t found any other drawbacks with the Armadillo for me. And even those two drawbacks aren’t a big deal because I have another rig I can use with larger cylinders and when diving backmount.

While the Armadillo runs a little more than most of the other sidemount rigs on the market, but by the time you get done adding the usual modifications being done on some of the other rigs, you’re paying almost as much for one of those as you are for an Armadillo. The Armadillo isn’t for everyone, but I do encourage anyone in the market for a sidemount rig to try it out before making a commitment.

Honestly, we never gave it any thought before. None of our scuba instructors had ever mentioned carbon monoxide contamination during any of our scuba courses. And, as far as we knew, no one was getting injured or dying from CO poisoning during dives. We were very wrong. Just in the past few years there have been three CO related deaths and two injuries that we know of. That’s without doing any research. There are likely more. There are also likely to be many injuries and possibly deaths that just weren’t investigated enough to discover CO was the culprit.

How does CO get in our scuba cylinders?

There are a few ways carbon monoxide can get into our scuba cylinders. The most common causes are running a vehicle near the compressor air intake (vehicle exhaust is comprised mainly of CO) and running a compressor so long it starts to produce CO. While many compressors have filters in place to filter our contaminants in the air, they don’t always work, and sometimes may even contribute to the contamination.*

Regardless of how carbon monoxide gets into the scuba cylinder, once it’s there it’s dangerous to the diver. The commonly accepted level of CO in regular grade E scuba air is 10 parts per million (ppm). Anything above this can be dangerous, even deadly, to the diver breathing the contaminated air. While that amount of CO is harmless at the surface, as with every other gas, as you descend the concentration of the gas multiplies with the pressure increase (Dalton’s Law). That 10 ppm becomes toxic to the diver with the increase in proportion.

The commonly accepted level of CO in oxygen safe scuba air is 3 ppm. The reason for the lower limit is that CO, being a contaminant, will increase the risk of fire or explosion if combined with rich percentages of oxygen. While greater than 3 ppm is “safe” to breathe at depth, it is not safe to mix with oxygen.

The way we look at it is if there’s any carbon monoxide in the gas we are about to breathe underwater there’s a problem. There should be no CO moving through the compressor filters and to find any indicates there is a problem somewhere that will only get worse.

What does CO do to our bodies?

During the respiratory process we normally breathe in air containing approximately 21% oxygen and 79% nitrogen (there are traces of other inert gasses). Only about 5% of the oxygen gets used by our bodies and binds to our hemoglobin. Hemoglobin is the part of our blood that carries oxygen throughout our bodies to oxygenate our organs and tissues. The problem with carbon monoxide is that hemoglobin likes it a lot more than it likes oxygen. In fact, hemoglobin has an affinity for CO that is 225 times greater than for oxygen. So when there is both oxygen and CO in a scuba cylinder, the CO will always win. This means oxygen will not bind with our hemoglobin and our organs and tissues will not get oxygenated. Essentially, our bodies become starved of oxygen leading to a black out. Under water this leads to drowning

When people come to the emergency room for exposure to carbon monoxide we have them breathe 100% oxygen for at least 12 hours to wash it out of their systems. The treatment for a diver who has been exposed to CO and survived long enough to get back to the surface is to put the diver in a hyperbaric chamber to expose him/her to 100% oxygen while at pressure.

So how do you detect CO?

Carbon Monoxide Analyzers

There are currently two carbon monoxide analyzers being manufactured specifically for scuba diving purposes.

Analox EII CO Carbon Monoxide Analyzer

C-Squared CO Analyzer (being sold as an Oxycheq analyzer)

Both analyzers do the same job and are in the same price range. They are both compact and easy to travel with. Both require sensor replacement about every two years. So it really doesn’t matter which one you choose.

“But I only dive in the US so I don’t need one”

The two cases we know of that we stated were injuries occurred in the US at a popular dive shop. The shop hadn’t had any issues with their gas before those incidents or since then. It happens! For about $300 you can make sure it doesn’t happen to you!

We are so passionate about this issue because we had a friend fall victim to CO poisoning. He didn’t get injured. He died. His maximum depth on his last dive was 40 feet. His actions showed he knew something was wrong just seconds before he passed out, but there wasn’t enough time for him to react before blacking out. And even if he had, once CO gets in your body the only treatment is exposure to high percentage of oxygen, something that wasn’t going to happen on the dive. A CO analyzer would have prevented his death. A CO analyzer can prevent yours.

* See the following article for more information on how compressors can create carbon monoxide –
Gas Analysis – Keeping yourself safe while cave diving!

At Chipola Divers we test our gas quarterly as well as analyzing every cylinder we fill for carbon monoxide.