Cryptic crossword No 3,830

Across

1. "Get Therapy!" we hear from oceanic algae (3,4)
2. Agreement about involuntary movement is before religious enlightenment (9)
3. Every other endorsee spied (4)
4. Countdown interrupted by temperature initially. Ask about madness? (3-4,3)
5. Strangely almost now yearn for irritant (7)
6. Youngsters ruining premise (7)
7. Get dressed backwards as model and you enter tennis tournament (10)
8. Elsie almost reversed into dogs? (4)
9. Spooner skeptical at gallery, leaves quickly (4,3)
10. Hammerstein lost Rogers ultimately in a musical instrument (7)
11. All together showing audible disdain. "It is backwards!" (5)
12. In the end, I rough up topless Colin. He's a fascist. (9)
13. Grab some grub in Goa? Absolutely. (5)
14. Semi-known celebrity hanging around youth club on bike (7)

Down

1. Nothing about reassignment of sailor left redistribution impossible (15)
2. Impulse in spell using first cauldron (8)
3. Is growth in conflict supported by Eliot? (5)
4. Apathetic text response in tiny part of town in Oxfordshire (6)
5. Funny story: A nude came to sing. Badly! (7,8)
6. Giving retort in envy of killer (8)
7. Green cheese? (5)
8. About turn after song led captured soldier to military might (8)
9. Criminal got six-pack before dead writer departed (9)
10. Head North in ocean expedition to find molluscs (6)
11. On Tumblr: "To my cis bi mutual" (9)
12. Ex-Alaskan governor corralling Greenpeace about scaly mammal (8)
13. Supports walks (6)
14. Harmony with Democrat destroyed. It's messy (6)