Trying to Lower my SPL Part II and Repeatability in Swim Training

Yesterday, the day after my longer swim with LAMVAC’s annual 10K swim, I was feeling a bit tired. Still I went to the pool to limber up and try to lower my SPL again on a 25y pool. Based on my previous attempt and hitting 10 SPL, I decided to try to figure out what my tempo was at that SPL so that I could use my tempo trainer to help me figure out how to maintain that SPL and increase tempo.
By the way, I have figured out that the tempo trainer, in concert with counting strokes for a given length, is an excellent way to determine if you are working out at a level that is consistent with past workouts. On my bike I know I can do this with my Computrainer and training by watts; on running, I have the relentless treadmill to repeat training conditions, and also measured distances and times on either the track or known running paths. For a long time, I didn’t have a good way of doing that with swimming. I only had swim times per length or lap, but I don’t think that is good because I may be swimming with more or less efficiency across workout days but yet still hit the same time for a length or lap. Now, with the tempo trainer and counting strokes, I have a more precise measure as to how I’m swimming, how much effort I am putting into that interval, and even know when I should get out of the pool because I’m tiring.
My reason, thus, for determining my tempo at my 10 SPL is to figure out how to maintain SPL while increasing tempo, which should mean that I am maintaining efficiency while increasing my speed.
I had a pleasant surprise though; I hit 9 SPL! Here are my results:
Tempo 2.6 seconds:
11, 9 strokes
10, 9
9, 9
Tempo 2.5 seconds:
10, 9 strokes
10, 9
9, 9
Tempo 2.4 seconds:
10, 9 strokes
9, 9
9, 9
Tempo 2.3 seconds:
10, 10 strokes
10, 10
10, 10
I began at 2.6 seconds on my tempo trainer, which is almost unbearably slow. I knew my 10 SPL was also at a very slow tempo, so I just started here. Then I increased it by .1 seconds, doing 6×25 at each tempo. I flipped flop for a while between 9 and 10 SPL and eventually could not maintain 9 SPL at 2.3 seconds. This is my critical point at which I need to see if I can pull it down to 9 SPL at some point.
Some notes:
1. I need to relax more and not anticipate the beep of my tempo trainer. This caused me to lose balance as my body began to turn in anticipation of the beep coming but I was conditioned to swim at a faster tempo and I would turn too soon, resulting in an unbalanced position while gliding and creating drag.
2. My body was unstable and I need to learn to maintain my glide position and balance in the water for longer. I got better at this as my session went on. Also, being tired from the previous day’s swim session didn’t help.
3. For some reason, I had a decently coordinated switch with my left hand driving forward/right hand stroking back, but my right hand driving/left hand stroking was terrible. Bad hip drive with bad arm drop, and even bad beginning body position because of item 1 above. I need to make sure my switch/stroke is perfectly coordinated. Swimming super slow is tough!
4. I need to hang my head more; at times I seemed to lift up and I know my hips are also dropping as a result, creating more drag. This seemed to happen intermittently.
5. Relaxing is key and maintaining perfect balance, slightly on either side as my arm recovers overhead, so that I just glide with minimal water disturbance and drag.
6. Sometimes my feet would start to drift apart, mostly in anticipation of the beep and wanting to do a kick. But the beep wouldn’t come and then my kick was cocked for longer than it need be, creating more drag. Need to keep them together for more streamlining.
7. Breathing still slows me down. I need to practice doing this more at slower speeds.
8. Despite the problems, there were times I felt that my stroke and glide between beeps was perfect. I would stroke with a perfect switch and arm drop, and then I would be in perfect gliding position as my arm recovered overhead and timed the next beep perfectly. This is the situation I need to imprint and work on repeating over and over again.